General:
* Footwear
* Boots
* Sneakers
* Kicks (slang)
* Trainers (UK)
* Slippers
Formal:
* Pumps
* Oxfords
* Loafers
* Sandals
Informal:
* Crocs
* Flip-flops
* Thongs (Australia)
* Sandalettes
Specific:
* Heels
* Wedges
* Moccasins
* Espadrilles
Let me know if you're looking for a specific type of shoe and I can help you find a more accurate word.