Back in the tubeless old-days it was common enough to use Gorilla tape, which is much like duct tape but with more adhesive. The idea was two loops of that would build up the BSD of a non-tubeless rim so it was tight enough to seal. I wouldn't do it with anything up-to-date

Electrical tape was tried by the tubeless crowd and rejected for many reasons. It had few redeeming features. Pretty weak, didn't last, easily spoiled adhesive

I used Kapton once and found it pretty stiff material. It didn't want to stretch to cover the shape of the rim interior.

So, I use Stan's. Or whatever on the shelf is similar

Velocity themselves made spoke hole plugs that replace rim strips. Do they still? haven't looked. Dunno what has happened to those in the tubeless era

Still available but not for tubeless use. https://www.velocityusa.com/product/...ries/veloplugs

I found that the 2-year-old strapping tape that I used for my rim possibly contributed to some punctures in my inner tube. Today I got a flat and looked at the inner tube. It had whitish discoloration matching the edges of the rim tape and holes for the spoke where the tape had an indentation. Appeared that the edges along the whitish discoloration had a sort of seam cut into it. I theorized that as the strapping tape gets older perhaps the edges start to lift up and dig into the inner tube. They were two pictures along that sort of cut.

Edit: at the time I swapped the damaged inner tube with a spare and after a week the spare also developed the same type of slit with a puncture but had a different location. I looked at the rim tape and the edge was clearly upturned and folded over at the location of the puncture. As a quick fix I used a knife to cut off the edges of the rim tape. When I have more time I will replace the entire tape. I believe what compounded the problem was I had two or three overlapping layers lined up directly over each other so that the edge became stronger and sharper. Instead next time I might offset two or three wraps slightly so that the edges don't align to create a more flexible edge.