Some in home ideas to help develop compositional and technical skills:

Water drops into colored water Running water Water drop reflections… try through glass Flowers Still life, veggies and fruit or other objects you are interested in Anything macro: insects, coins, food and food parts, smoke, i even did a series on dripping elmers glue, pencils, rubber bands… Pets Perspective challenges: toys, glassware, bottles, food Products: clothing, accessories, alcohol, glassware, shoes. People, if you have a willing accomplice: i saw a series of people in boxes that is quite interesting. One or two lights shown on anything, try different angles Depth of field practice with various lenses at various distances to internalize how dof changes with changing circumstances. Try various styles: flatlays, night, hanging objects, spinning objects, backlit, portrait.

So many options.