Unless you want to be on a supporters bus, there's still direct Alsa busses (Spanish public bus operator) with spaces mate:any spare seats on a bus going from malaga to seville and back again? my bus got canceled lol
Wherever you want to go - Alsa
Buy bus tickets at the best price. At Alsa we offer bus rental, travel deals, on-board services and information on routes and schedules.
www.alsa.com
Also quite a few trips on Bla Bla Car: https://www.blablacar.co.uk/