not sure where you're looking to only find a 'few' functionalised filaments.
There are so many flexible filaments I've just not got round to testing more than half. There are at least 4 conductive filaments, then you've got the carbon fibre and grapehene, too many varieties of pla too mention.

Rather than needing more filament types - I need a helluva lot more time to test the ones I've already got and there are more coming out each week.

As far as antibacterial goes - any filament with copper in is not only antibacterial it's anti viral.

I will disagree with bassna's desire for post processing filaments. I hate all the sanding and buffing - I just want it to print and look metallic :-)

Check out globalfsd.com for more funtionalised filaments than you can shake a 3d printed stick at.