I'll reiterate, but some of the best battle field control spells are the Summon Monster series and the Summon Nature's Ally series. For example, if you can pop out a huge creature to grapple a medium one, that medium creature isn't going to make the check. You can also summon things like dire wolves to both attack and trip opponents.
Then there's crazy like Summon Monster IV's Voor. 4 tentacle attacks, 2 claws, it's large sized and has reach. You can sit there tripping everything it threatens for a long time.
Another great one is Evard's
Black Tentacles. I've also been a fan of Wall of Smoke.