We live in a cold weather state. In our basement we can do hands progressions, simple glove/footwork reps, tags for middle infielders on steal attempts, catchers receiving & blocking drills, band work, double play footwork and transfers, pitcher's pickoff moves, drills for first baseman including footwork around the bag and receiving the ball on pickoff throws, underhand flip drills for MI's and 1B's, plus hitting drills including tee work and front toss with indoor nerf type balls.... In our backyard we can do all of that plus simple route work for outfielders, footwork on popups
The list is probably endless. Point is, if there is a will there is a way.