You may need to customize this list based on the time of your workout and surrounding activities.
 
Towel
Change of Clothes
Socks
Underwear
Belt
Jewelry
Nice Hair Clip(you neverknow)
Shampoo
Conditioner
Hairbrush
Deodorant
Lotion
Roll-on perfume*
Nail file*
Q tips*
Glassess/Contact case/Solution*
Tissues*
Tylenol*
Make up Bag
Eyelash Curler(yes I pack this separate everywhere I go)
Sweat Rag
Hair Ties*
Blender Bottle
Coin Bag($1 bills & quarters)
Headphones
MP3
Tampons*
Band Aids*
Empty plastic bags for dirty/wet clothes
Lock
 
(Optional)
Razor*
Pre/Post Workout Drink
Meal Bars
Leave in Hair Conditioner or other styling product
Toothbrush/Toothpaste*
OR
Colgate Wisp
Supplements*
 
* Items for small unattached bag which can be transferred to another bag for overnight trips