They’re not cheap but I quite like the titanium screws from S-PARTS. I’ve only found them on sale through their official Tmall store so buyers outside of Greater China may be out of luck here. Though I’m pretty sure they have some international presence because Ti-Parts on Carousell Singapore is almost certainly supplied by them. S-PARTS is growing in credibility imo because many new high end boutique components makers from China are now using their screws. For example, the new EXS ULTRA-RR stem and VFV Deep-V seatpost both advertise their use of S-PARTS screws.
There is also a brand called RISK (probably also supplied by S-PARTS?) on Taobao/Tmall/Aliexpress that sells a smaller selection of titanium screws compared to S-PARTS.
I've ordered from S-PARTS -
https://spartsti.com - four times. Outside of slow shipping (almost four weeks from order to arrival) my first three orders went smoothly. Its online chat agent was also helpful in sourcing parts for me, and was always quick to respond.
My fourth order took two months to arrive, and a bolt ($3.99 USD) was missing. The online chat agent agreed to send me the missing bolt (I'd pay for shipping) and created a custom link for me to place the order. The link was incorrect; it led me to ordering an item I didn't want. When I notified the agent of the incorrect link, the agent ghosted me. For two weeks, all online chat messages and e-mails to S-PARTS were ignored.
While S-PARTS pre-sales customer service is good, its post-sales customer service is garbage. I'm avoiding ordering from the company forever. Take my experience for what you will.