Use a super O flute bit from Onsrud. You can cut most plastics. Run the router at 12k or less. Feed rate high as you dare. Acrylic cuts reasonable well as does UHMW and HDPE. Look at the Onsrud site and find the plastic cutting info as well as lots of good info on other materials. https://www.onsrud.com/xdoc/FeedSpeeds
Don't know your application so can't recommend a material.
You can also cut aluminum with the that bit and a router. Slower feed rates and small cuts are your friend for this.