This service lets you find columns within VO TAP services by UCD or description words.
For UCD, you will frequently want to use regular expression matches (e.g., ~ pos.eq*). Note that, unfortunately, some services still use old-style UCDs (see Moving to UCD1+). Thus, to find all interesting columns, you may need to search multiple times.
The table can also be queried using TAP or on our ad-hoc ADQL service.