To name a few that aren't being made any more . . .
Mossberg - made about a dozen different semis, some DM, some tubular. Reliable and accurate. Models 51, 151, etc.
Browning - the TakeDown, and a full-sized rifle called the BAR-22. Very nice.
Weatherby XXII - magazine or tubular. Expensive, high end rifles.
Winchester - models 74 & 77, 190, 290, 490, to name a few. The Win 63 is considered to be one of the finest semis ever built/designed.
Remington - Speedmaster tubular, classic. They also did a version of the Browning takedown auto. Nylon 66 has it's own following.
Anschutz - 520, or something like that. Also came in CIL markings (300?).
Gevarm - an open bolt shooter.
Cooey - the 64. Very common, just needs a new magazine every so many thousands of rounds.
Marlin, Savage, Lakefield, Tyrol, Voere, Franchi, etc - just about everybody has made a semi at some point.
Do some searching, check out the 'net, Gunbroker, etc. Just remember that .22 semis are filthy little buggers compared to any closed breech action. Keep your eyes open and you can find a high quality used semi without too much effort.