diff --git a/easybuild/easyconfigs/l/LLVM/LLVM-20.1.7-GCCcore-14.2.0.eb b/easybuild/easyconfigs/l/LLVM/LLVM-20.1.7-GCCcore-14.2.0.eb
new file mode 100644
index 000000000000..2264e5ee9082
--- /dev/null
+++ b/easybuild/easyconfigs/l/LLVM/LLVM-20.1.7-GCCcore-14.2.0.eb
@@ -0,0 +1,84 @@
+name = 'LLVM'
+version = '20.1.7'
+
+
+homepage = "https://llvm.org/"
+description = """The LLVM Core libraries provide a modern source- and target-independent
+ optimizer, along with code generation support for many popular CPUs
+ (as well as some less common ones!) These libraries are built around a well
+ specified code representation known as the LLVM intermediate representation
+ ("LLVM IR"). The LLVM Core libraries are well documented, and it is
+ particularly easy to invent your own language (or port an existing compiler)
+ to use LLVM as an optimizer and code generator."""
+
+toolchain = {'name': 'GCCcore', 'version': '14.2.0'}
+toolchainopts = {
+    # 'cstd': 'gnu++11',
+    'pic': True
+}
+
+source_urls = ['https://github.com/llvm/llvm-project/releases/download/llvmorg-%(version)s/']
+sources = [
+    'llvm-project-%(version)s.src.tar.xz',
+]
+patches = [
+    'LLVM-18.1.8_envintest.patch',
+    'LLVM-19.1.7_libomptarget_tests.patch',
+    'LLVM-19.1.7_clang_rpathwrap_test.patch',
+]
+checksums = [
+    {'llvm-project-20.1.7.src.tar.xz': 'cd8fd55d97ad3e360b1d5aaf98388d1f70dfffb7df36beee478be3b839ff9008'},
+    {'LLVM-18.1.8_envintest.patch': '8e25dfab8a29a860717b4bd2d8cdd0e795433766d7fffbda32d06a2bde47058d'},
+    {'LLVM-19.1.7_libomptarget_tests.patch': '79a67c118d034cfb74e255696369150c73432d2b422f4834efacb26f7904edbf'},
+    {'LLVM-19.1.7_clang_rpathwrap_test.patch': '5ee6a87ec8ff1c8b736ffe0513aa2098bd2b83a1ffc647a1ad2cf966f567e8a1'},
+]
+
+builddependencies = [
+    ('binutils', '2.42'),
+    ('Python', '3.13.1'),
+    ('CMake', '3.31.3'),
+    ('psutil', '7.0.0'),  # Needed to enable test timeout in lit
+    ('lit', '18.1.8'),
+    ('git', '2.49.0'),
+]
+
+dependencies = [
+    ('libxml2', '2.13.4'),
+    ('ncurses', '6.5'),
+    ('zlib', '1.3.1'),
+    ('Z3', '4.13.4'),
+    ('zstd', '1.5.6'),
+]
+
+build_shared_libs = True
+
+bootstrap = True
+full_llvm = False
+build_clang_extras = True
+build_runtimes = True
+build_lld = True
+build_lldb = True
+build_bolt = True
+build_openmp = True
+build_openmp_tools = True
+build_openmp_offload = True
+use_polly = True
+
+python_bindings = True
+
+build_targets = ['all']
+# disable_werror = True
+
+skip_all_tests = False
+skip_sanitizer_tests = True
+test_suite_max_failed = 10
+test_suite_timeout_single = 5 * 60
+test_suite_ignore_patterns = [
+    "X86/register-fragments-bolt-symbols.s",
+    "modularize/ProblemsCoverage.modularize",
+    "Driver/atomic.f90",
+    "Driver/gcc-toolchain-install-dir.f90",
+    "api_tests/test_ompd_get_icv_from_scope.c",
+]
+
+moduleclass = 'compiler'
diff --git a/easybuild/easyconfigs/l/lit/lit-18.1.8-GCCcore-14.2.0.eb b/easybuild/easyconfigs/l/lit/lit-18.1.8-GCCcore-14.2.0.eb
new file mode 100644
index 000000000000..b8a830d9c568
--- /dev/null
+++ b/easybuild/easyconfigs/l/lit/lit-18.1.8-GCCcore-14.2.0.eb
@@ -0,0 +1,35 @@
+easyblock = 'PythonBundle'
+
+name = 'lit'
+version = '18.1.8'
+
+homepage = 'https://llvm.org/docs/CommandGuide/lit.html'
+description = """lit is a portable tool for executing LLVM and Clang style test suites, summarizing their results, and
+providing indication of failures."""
+
+toolchain = {'name': 'GCCcore', 'version': '14.2.0'}
+
+builddependencies = [
+    ('binutils', '2.42'),
+]
+
+dependencies = [
+    ('Python', '3.13.1'),
+]
+
+exts_list = [
+    ('ptyprocess', '0.7.0', {
+        'source_tmpl': '%(name)s-%(version)s-py2.py3-none-any.whl',
+        'checksums': ['4b41f3967fce3af57cc7e94b888626c18bf37a083e3651ca8feeb66d492fef35'],
+    }),
+    ('pexpect', '4.9.0', {
+        'checksums': ['ee7d41123f3c9911050ea2c2dac107568dc43b2d3b0c7557a33212c398ead30f'],
+    }),
+    (name, version, {
+        'checksums': ['47c174a186941ae830f04ded76a3444600be67d5e5fb8282c3783fba671c4edb'],
+    }),
+]
+
+sanity_check_commands = ['lit -h']
+
+moduleclass = 'tools'
diff --git a/easybuild/easyconfigs/m/Mesa/Mesa-25.1.3-GCCcore-14.2.0.eb b/easybuild/easyconfigs/m/Mesa/Mesa-25.1.3-GCCcore-14.2.0.eb
new file mode 100644
index 000000000000..5754c7e7ee0d
--- /dev/null
+++ b/easybuild/easyconfigs/m/Mesa/Mesa-25.1.3-GCCcore-14.2.0.eb
@@ -0,0 +1,67 @@
+# This is a Mesa using software rendering via Gallium-DRI and libglvnd
+# - libglvnd can dynamically choose between system-installed NVidia
+# libGLX/libEGL or the software renderers provided by this Mesa
+# - EGL is available
+#
+# Software renderers enabled (swr deprecated as of v22):
+# - llvmpipe: uses LLVM for JIT code generation (multi-threaded)
+# - softpipe: a reference Gallium driver
+# Default renderer is llvmpipe. To use softpipe, set the environment
+# variable GALLIUM_DRIVER=softpipe
+
+name = 'Mesa'
+version = '25.1.3'
+
+homepage = 'https://www.mesa3d.org/'
+description = """Mesa is an open-source implementation of the OpenGL specification -
+ a system for rendering interactive 3D graphics."""
+
+toolchain = {'name': 'GCCcore', 'version': '14.2.0'}
+
+source_urls = [
+    'https://archive.mesa3d.org/',
+    'https://archive.mesa3d.org/older-versions/%(version_major)s.x/',
+]
+sources = [SOURCELOWER_TAR_XZ]
+checksums = ['ffcb6cadb5fd356d56008e6308641dfe4b2929f30139f6585436ca6e3cddba7f']
+
+builddependencies = [
+    ('binutils', '2.42'),
+    ('Meson', '1.6.1'),
+    ('Ninja', '1.12.1'),
+    ('flex', '2.6.4'),
+    ('Bison', '3.8.2'),
+    ('pkgconf', '2.3.0'),
+    ('Mako', '1.3.10'),
+    ('libxml2', '2.13.4'),
+    ('expat', '2.6.4'),
+    ('gettext', '0.24'),
+    ('glslang-SPIRV', '15.3.0'),
+    ('PyYAML', '6.0.2'),
+]
+
+dependencies = [
+    ('zlib', '1.3.1'),
+    ('zstd', '1.5.6'),
+    ('libdrm', '2.4.125'),
+    ('libglvnd', '1.7.0'),
+    ('libunwind', '1.8.1'),
+    ('LLVM', '20.1.7'),
+    ('X11', '20250521'),
+    ('Wayland', '1.23.92'),
+]
+
+configopts = "-Dplatforms=x11,wayland -Dvulkan-drivers='swrast' -Dvulkan-layers='device-select' "
+configopts += "-Dllvm=enabled -Dshared-llvm=enabled -Dlibunwind=enabled -Degl=enabled -Dglvnd=enabled -Dglx=auto "
+configopts += "-Dvideo-codecs=vc1dec,h264dec,h264enc,h265dec,h265enc,av1dec,av1enc,vp9dec "
+
+# Easybuild will automatically add appropriate Gallium drivers for the processor architecture of the host
+# If you need a different configuration, it possible to override those values by setting your own configopts
+# configopts += " -Dgallium-drivers=auto"
+
+# symlink indirect to mesa GLX, similar to Debian, see
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=881789
+# This helps in certain X forwarding situations (e.g. XQuartz)
+postinstallcmds = ["ln -s libGLX_mesa.so.0 %(installdir)s/lib/libGLX_indirect.so.0"]
+
+moduleclass = 'vis'
diff --git a/easybuild/easyconfigs/x/Xvfb/Xvfb-21.1.18-GCCcore-14.2.0.eb b/easybuild/easyconfigs/x/Xvfb/Xvfb-21.1.18-GCCcore-14.2.0.eb
new file mode 100644
index 000000000000..4f1021340606
--- /dev/null
+++ b/easybuild/easyconfigs/x/Xvfb/Xvfb-21.1.18-GCCcore-14.2.0.eb
@@ -0,0 +1,126 @@
+easyblock = 'Bundle'
+
+name = 'Xvfb'
+version = '21.1.18'
+
+homepage = 'https://www.x.org/releases/X11R7.6/doc/man/man1/Xvfb.1.xhtml'
+description = """Xvfb is an X server that can run on machines with no display hardware and no physical input devices.
+ It emulates a dumb framebuffer using virtual memory."""
+
+toolchain = {'name': 'GCCcore', 'version': '14.2.0'}
+
+builddependencies = [
+    ('binutils', '2.42'),
+    ('pkgconf', '2.3.0'),
+    ('Python', '3.13.1'),
+    ('Meson', '1.6.1'),
+    ('Ninja', '1.12.1'),
+    ('libxslt', '1.1.42'),
+    ('gettext', '0.24'),
+    ('Bison', '3.8.2'),
+]
+
+dependencies = [
+    ('X11', '20250521'),
+    ('pixman', '0.46.2'),
+    ('libdrm', '2.4.125'),
+    ('Mesa', '25.1.3'),
+    ('nettle', '3.10.1'),
+    ('libunwind', '1.8.1'),
+    ('XZ', '5.6.3'),
+]
+
+default_easyblock = 'ConfigureMake'
+
+local_xvfb_configopts = "--enable-xvfb --disable-xorg --disable-xnest --disable-xwin "
+local_xvfb_configopts += "--disable-dri --disable-dri2 --disable-dri3 --disable-libunwind "
+local_xvfb_configopts += "--with-fontrootdir=%(installdir)s/share/fonts/X11"
+
+# use 'make V=1' to see compiler commands
+local_xvfb_buildopts = "V=1 "
+
+# use static libraries for nettle & libunwind, so avoid errors like "No rule to make target '-lnettle'"
+local_xvfb_buildopts += 'SHA1_LIBS="$EBROOTNETTLE/lib*/libnettle.a" '
+local_xvfb_buildopts += 'LIBUNWIND_LIBS="$EBROOTLIBUNWIND/lib*/libunwind.a $EBROOTXZ/lib*/liblzma.a"'
+
+default_component_specs = {
+    'sources': [SOURCE_TAR_GZ],
+    'start_dir': '%(name)s-%(version)s',
+}
+
+local_font_misc_preconfigopts = "export PKG_CONFIG_PATH=%(installdir)s/lib/pkgconfig:$PKG_CONFIG_PATH && "
+local_font_misc_preconfigopts += "export PATH=%(installdir)s/bin:$PATH && "
+
+components = [
+    ('mkfontscale', '1.2.3', {
+        'source_urls': ['https://www.x.org/archive/individual/app/'],
+        'checksums': ['3a026b468874eb672a1d0a57dbd3ddeda4f0df09886caf97d30097b70c2df3f8'],
+    }),
+    ('mkfontdir', '1.0.7', {
+        'source_urls': ['https://www.x.org/archive/individual/app/'],
+        'checksums': ['bccc5fb7af1b614eabe4a22766758c87bfc36d66191d08c19d2fa97674b7b5b7'],
+    }),
+    ('bdftopcf', '1.1', {
+        'source_urls': ['https://www.x.org/archive/individual/app/'],
+        'checksums': ['699d1a62012035b1461c7f8e3f05a51c8bd6f28f348983249fb89bbff7309b47'],
+    }),
+    ('font-util', '1.4.1', {
+        'source_urls': ['https://www.x.org/archive/individual/font/'],
+        'checksums': ['f029ae80cdd75d89bee7f7af61c21e07982adfb9f72344a158b99f91f77ef5ed'],
+    }),
+    ('font-misc-misc', '1.1.3', {
+        'source_urls': ['https://www.x.org/archive/individual/font/'],
+        'checksums': ['bece4a9482b3cb6f7fad2164fd3b394d22dfe1ad2f96f60030a703bcff30f5a5'],
+        'preconfigopts': local_font_misc_preconfigopts,
+    }),
+    ('xkbcomp', '1.4.7', {
+        'source_urls': ['https://www.x.org/archive/individual/app/'],
+        'checksums': ['00cecc490fcbe2f789cf13c408c459673c2c33ab758d802677321cffcda35373'],
+    }),
+    ('xkeyboard-config', '2.45', {
+        'easyblock': 'MesonNinja',
+        'source_urls': ['https://www.x.org/archive/individual/data/xkeyboard-config/'],
+        'sources': [SOURCE_TAR_XZ],
+        'checksums': ['169e075a92d957a57787c199e84e359df2931b7196c1c5b4a3d576ee6235a87c'],
+        'configopts': '-Dxorg-rules-symlinks=true',
+    }),
+    ('xauth', '1.1.3', {
+        'source_urls': ['https://www.x.org/releases/individual/app/'],
+        'checksums': ['88c288e0a30bf071631118644f5232cae3a79713a7c82dd31a236e8e2c6fca15'],
+    }),
+    ('libxcvt', '0.1.3', {
+        'easyblock': 'MesonNinja',
+        'source_urls': ['https://www.x.org/archive/individual/lib/'],
+        'sources': [SOURCE_TAR_XZ],
+        'checksums': ['a929998a8767de7dfa36d6da4751cdbeef34ed630714f2f4a767b351f2442e01'],
+    }),
+    (name, version, {
+        'source_urls': ['https://www.x.org/releases/individual/xserver/'],
+        'sources': ['xorg-server-%(version)s.tar.gz'],
+        'patches': [('xvfb-run', '.')],
+        'checksums': [
+            'c8591ceb70b177440062406542fe52ba60212f217f27f8f802dd20373ca9e74b',  # xorg-server-21.1.14.tar.gz
+            'fd6d13182b77871d4f65fccdaebb8a72387a726426066d3f8e6aa26b010ea0e8',  # xvfb-run
+        ],
+        'start_dir': 'xorg-server-%(version)s',
+        'configopts': local_xvfb_configopts,
+        'buildopts': local_xvfb_buildopts,
+        'installopts': local_xvfb_buildopts,
+    }),
+]
+
+# enable exec permissions for xvfb-run after copying;
+# need to also enable user write permissions on xvfb-run to ensure that copying with preserved permissions works
+postinstallcmds = ["chmod u+w xvfb-run && cp -a xvfb-run %(installdir)s/bin/ && chmod a+x %(installdir)s/bin/xvfb-run"]
+
+sanity_check_paths = {
+    'files': ['bin/Xvfb', 'bin/xvfb-run'],
+    'dirs': ['lib/xorg', 'share/fonts/X11/misc', 'share/fonts/X11/util'],
+}
+
+sanity_check_commands = [
+    "xvfb-run --help",
+    "xvfb-run --error-file %(builddir)s/xvfb-run-test.err echo hello",
+]
+
+moduleclass = 'vis'