2.4 million distinct mainnet taproot outputs with amounts greater than 500K sats (at least once), in the last year.

Proof that I own one of them **, and a key image to prevent reuse, size 2.9kB and verified in 64ms!

The keyset takes up 155MB, but half that if binary.
Scanning raw blocks using RCasatta's tool:

https://github.com/RCasatta/blocks_iterator

... takes minutes but not too bad. Creating the proof is slow, I estimate 5-8 minutes on my laptop. Can def be improved.

Work continues at https://github.com/AdamISZ/aut-ct 

** (Ok, i cheated and inserted a key of my own into the list, instead of creating a new utxo. Sue me!)