Currently there is no way to search for or filter builds. There is a builds page in the dashboard, https://app.saucelabs.com/dashboard/builds but it has no way to filter builds by anything other than owner, and we have a very large number of tests that use a shared Pipeline account.
We have many builds that fit the form factor PR-1111-X, which would be the build for revision X of PR-1111. It would be very useful to have a simple search for matching build IDs to bring up a list of builds matching an ID pattern or tag value or something, so as to compare related builds.
As it is currently, unless it's a very recent build, the only way to find a build is to use the Archives page to search for an arbitrary test session with a matching build ID, and then click through to the build page from the test session, and that's both convoluted and requires the user to know exactly a single build ID.