If you want to step (deeper) into modular synthesis, Omri Cohen is one of the best teachers for that on YouTube. If you should not know, VCV Rack is a free software version for modular synthesis and there’s an iOS port available called MiRack.
Gleetchlab is a modular performance DAW dedicated to glitch and experiemental music (20 Euro).
FamiStudio is a free simple, DAW-style, music editor for the Nintendo Entertainment System. It is designed for both chiptune enthusiasts and the NES homebrew community.
MPC Beats, the fully featured, beat-making software based on the legendary MPC workflow to quickly make great sounding beats.
Download MPC software for free at AKAI. It is a fully featured, beat-making software based on the legendary MPC workflow to quickly make great sounding beats.
Caustic 3 is a music creation tool inspired by rack-mount synthesizers / samplers rigs. Everything is real-time and optimized for mobile devices.
But the desktop version is free (No support)