Hi Red!
My favorite buddies are [mwcard=MW1C26]Necropian Vampiress[/mwcard] and [mwcard=MWSTX1CKC01]Bridge Troll[/mwcard]. I know that [mwcard=MW1C34]Steelclaw Grizzly[/mwcard], [mwcard=MW1C07]Cervere, The Forest Shadow[/mwcard] and [mwcard=FWC09]Iron Golem[/mwcard] have been other people's favorites in the past. The reason I like the other two better is that you don't have to play creature support as much since they can take care of themselves with the regeneration and the vampirism. Granted, the troll could really benefit from a [mwcard=MW1E36]Rhino Hide[/mwcard].
The important thing to look for in a buddy for the Forcemaster is efficiency to spell book cost. Triple for non-Mind creatures is very steep--and everyone knows it! 5 dice or more is really the tipping point, Cervere gets a pass because of Defense, Fast AND Elusive. This is also where Bridge Troll really shines. Everyone (except Beastmaster) pays at least 5 to put it in their book. Forcemaster only pays 9! Which is not even double what other people pay.
Some other tips for the Forcemaster:
Your Deflect ability is nice but there will be games where it fails every single time. If you have space and actions you may want to try [mwcard=MW1J09]Temple of the Dawnbreaker[/mwcard].
Your Force Pull ability is amazing. Use it to separate your target from his guards or give one of your own creatures an 'extra move' for the turn. It can also be very handy in testing for Jinx as a Jinx can stop ANY quick spell.
Whatever book you build ask yourself if you can find room for Galvitar, Forcefield and Mind Control. These spells are feared by some and at the least irritating to your opponents. Academy has Arcane Ward that can make it an even bigger pain to get rid of these powerful spells.
Thoughtspores are fragile! Only put a range 1 spell on them in extreme circumstances. Range 2 is better. If your spore can protect itself with its attached spell that's even better.
As such a specialized mage you really need to put effort into understanding your opponent's strategy and eviscerating it with a precise strike. You cannot afford to waste actions! It is better to spend extra mana to not waste actions. Look to 2-for-1 spells and figure out if you can hack out a space for them: [mwcard=MWBG1I01]Cascading Force Wave[/mwcard], [mwcard=FWI04]Force Wave[/mwcard], [mwcard=MW1I20]Purify[/mwcard], [mwcard=MW1I21]Purge Magic[/mwcard] and maybe even [mwcard=MW1I11]Explode[/mwcard]!
If you plan on playing a bunch of upkeep spells make sure you buff your channeling and bring along a [mwcard=FWQ07]Psi-Orb[/mwcard]
Hope at least some of that helps. Forcemaster is my favorite lady. May you win the Mind games!