Until they discontinued it, I used the Philips Inspire Go. Since that's gone, I'm thinking seriously about the Pari eflow (ghastly expensive) but when I think about what college cost and that I need it for the rest of my life, it's tempting.
https://nebology.com/products/pari-erapid-nebulizer-system-with-eflow-technology

I also saw the Aura Portable at Save Rite Medical online.
https://www.saveritemedical.com/products/aura-portable-aerosol-nebulizer-52mm-x-52-5mm-x-126mm?_pos=3&_sid=5a6d5062a&_ss=r

There's a compressor based by Pari but I've read it v e r y slow.
https://www.saveritemedical.com/products/trek-s-portable-compressor-nebulizer-aerosol-system-standard?_pos=1&_sid=08703d2bd&_ss=r

I've also read that the mesh handheld portables don't deliver saline deep enough in the lungs so you might not get the same benefit as a compressor based. Apparently, the Pari eflow is an exception, people love it.