One of my favorite segments I have used in clinics is my sharing of conditioning equipment for softball players. Only a few items are needed and you can carry them inside your fielding glove. A tennis or racket ball, a jump rope, a surgical band, and a bag of beans (I like kidney beans best).
I'll share a quick explanation on the aids. You can get creative from there.
Jump rope is self-explanatory. Use it for 5-10 minutes at least 3 times a week.
A tennis or racket ball for a host of training and conditioning exercises. Use your imagination.
A surgical band for exercising. More than one for more resistance.
A bag of beans; this is the one you'll love. I use them for a hitting aid. Stand about 7-10 feet in front of your batter and toss the beans underhand. They have to swing and hit the beans. If they can hit a bean, they can hit a softball. Lima beans will work but the smaller red kidney beans are easier to toss and harder to hit. Use your imagination on all the benefits of them hitting beans. They're biodegradable and they double as bird seed so no need to pick them up. A 99-cent bag can last for many sessions and much lighter/easier to carry than a bucket of balls. lol. The girls love this drill.