diff --git a/eng/pipelines/libraries/helix-queues-setup.yml b/eng/pipelines/libraries/helix-queues-setup.yml
index f09ca254d9a0db..be64e32c7d721c 100644
--- a/eng/pipelines/libraries/helix-queues-setup.yml
+++ b/eng/pipelines/libraries/helix-queues-setup.yml
@@ -63,6 +63,7 @@ jobs:
           - (Debian.10.Amd64.Open)ubuntu.1604.amd64.open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-10-helix-amd64-bfcd90a-20200121150006
         - ${{ if or(ne(parameters.jobParameters.testScope, 'outerloop'), ne(parameters.jobParameters.runtimeFlavor, 'mono')) }}:
           - ${{ if eq(parameters.jobParameters.isFullMatrix, true) }}:
+            - (Centos.7.Amd64.Open)Ubuntu.1604.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:centos-7-mlnet-helix-20210714125435-dde38af
             - (Centos.8.Amd64.Open)Ubuntu.1604.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:centos-8-helix-20201229003624-c1bf759
             - RedHat.7.Amd64.Open
             - Ubuntu.1804.Amd64.Open
@@ -74,13 +75,10 @@ jobs:
             - (Debian.11.Amd64.Open)Ubuntu.1804.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-11-helix-amd64-20210304164428-5a7c380
             - (Mariner.1.0.Amd64.Open)ubuntu.1604.amd64.open@mcr.microsoft.com/dotnet-buildtools/prereqs:cbl-mariner-1.0-helix-20210528192219-92bf620
           - ${{ if eq(parameters.jobParameters.isFullMatrix, false) }}:
-            - (Centos.8.Amd64.Open)Ubuntu.1604.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:centos-8-helix-20201229003624-c1bf759
+            - (Centos.7.Amd64.Open)Ubuntu.1604.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:centos-7-mlnet-helix-20210714125435-dde38af
             - RedHat.7.Amd64.Open
             - (Debian.10.Amd64.Open)Ubuntu.1804.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-10-helix-amd64-20210304164434-56c6673
-            - (Debian.11.Amd64.Open)Ubuntu.1804.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-11-helix-amd64-20210304164428-5a7c380
             - Ubuntu.1804.Amd64.Open
-            - SLES.15.Amd64.Open
-            - (Fedora.34.Amd64.Open)ubuntu.1604.amd64.open@mcr.microsoft.com/dotnet-buildtools/prereqs:fedora-34-helix-20210913123654-4f64125
       - ${{ if or(eq(parameters.jobParameters.interpreter, 'true'), eq(parameters.jobParameters.isSingleFile, true)) }}:
         # Limiting interp runs as we don't need as much coverage.
         - (Debian.10.Amd64.Open)Ubuntu.1804.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-10-helix-amd64-20210304164434-56c6673