Amazon Leo is currently launching satellites. They have 396 in orbit but haven't started service. The constellation is going to be lots smaller than Starlink with 3236 total.

AST SpaceMobile is planning cellular in space. I think it is supposed to be faster than Starlink Direct-to-Cell but slower than regular Starlink. It uses fewer, 12 currently, 45 in 2027, and 248 total, larger and higher satellites.

China has two large 10,000+ constellations planned with hundreds already launched.