Yamaha and the after market 25mm valve shims by K&L and others seem to only be available in 0.05mm incremental thicknesses.
It is possible to order Triumph 25mm valve shims in 0.025mm increments.
I ordered a couple 2.625mm and 2.675mm shims from BikeBandit, and the order has shipped, so they do have them available.
The Triumphs that use 25mm shims are the current Thunderbird and current Bonneville variants, as well as the older 900/1200cc Hinckley engines (like my 2001 Thunderbird).
It did take Bikebandit 3 weeks to ship the order, so be cautious doing this if you have an engine torn down and waiting. And they are slightly more expensive than the K&L shims MiCarl has for sale.