'common' is relative, remember that the Warrior's XTRO incarnation (with the self-exploding cannon) is Cappie, so while the Warrior is technically a Lyran staple, and was invented in the Lyran Commonwealth, it's been in use so long it's sort of like a T-34 in that examples are wide-spread even in use in enemy nations as a common matter of course.
For my own 'short list':
Manticore-really makes the point about tracked tanks either way you want to lean-in the right hands (and bunkered up in the right place) it's a deadly mobile turret with some close in defense crit-soaks, but the armor isn't as heavy as the Patton, so it doesn't last as long once you've parked and bunkered.
(Remember kids, the hit table prefers you put your tracked vee in 'park' and just soak that return fire while the 'mechs do the moving. under earlier rules, this was suicide behavior, but with Total Warfare's changes, this is essentially 'how to run a tank')
Demolisher: common product, everyone owns at least one. Good for making a fixed position something that you only assault from outside 9 hexes. Keep in mind the movement profile is such that you won't be closing range even on an Urbanmech. find a spot your opponent must approach and park it there.
Striker: mobile missile turret, wheeled, movement through woods not advised, but in urban it makes a nice deployable turret that soaks return fire for a couple rounds before exploding.
Maxim: for your combined arms play needs, decent battle-taxi for unarmored troops.
For later eras:
Myrmidon: probably the best pre-dark-age tracked tank, enough movement to climb hills or move through woods without going to flank, enough armor to take a hit or two, enough punch to be worth using. SRM's for infernoes (against other vees, infantry formations and the like) General table/mercenary sales, so dirt common too.
Hawk Moth: General distribution/mercenary sales, long range and bare minimum for survivable VTOL use for speed. Actually DOES what the Yellowjacket was advertised for doing, (iow being an effective big-gun VTOL for ranged fire support/backup for recon elements)
There are others, but those are 'general issue' stuff you can find pretty much ANYWHERE, except the Clans, who have their own stuff.
