The most power full of the Illyrian tribes was Bardylis of the Dardanians which would make a great king for them.
Some flags I found that are pretty cool
The most common Illyrian sword
They are described to be much the same as the Tracians, there infantry is Greek/Barbaric styled and they mostly used Peltast and slingers
(I'm Albanian and we are required to learn about Illyrians.)