How flexible is the dm? Will he or she let you devise your own spells to fit the theme?
How about a spider sorcerer- spiderclimb, web, acid web, poisonweb, polymorph, poison/fear type spells...
"Wall" sorcerers could be neat, as could symbol/glyph oriented sorcerers.
How about a slaad-blood sorcerer? Protection from law, change self, shout (RIBBIT!), etc.
A sorcerer focused on teh funny- grease, Tasha's laughter, fools gold, magic mouth, etc.
Really, it depends on the campaign and the dm's flexibility. And, of course, on what you want your sorcerer to be like. Any ideas? (Other than the summoning focus, which you seem to have discarded.)