Craftsman never made Tappet wrenches in metric.
Same for Armstrong, who was the supplier for the Craftsman Tappet wrenches.
I’m not even sure if Matco did, back when Armstrong made the Matco stuff, and Matco got metric wrenches that Armstrong never offered.
I think the Facom/Proto thin wrench set was the closest set i found to a Metric Tappet wrench set.
https://www.protoindustrial.com/en/industrial-tools/Proto/Wrenches/Open-End-Wrench-Sets/FM-31.JE6T_Facom®-6-Piece-Metric-Tappet-Wrench-Set-/
Snap-On and some other truck brands offer Ultra thin forged wrenches and sets, but the wrenches are usually a bit pricey and don’t seem to turn up as much on eBay.
If you don’t need a long wrench, Check Nut wrenches are a thin wrench style that is sometimes thinner than a tappet wrench.
Martin makes them in the US out of forged steel.
Proto also sells them, although I think Proto probably sources them from Martin. The style goes back decades, but Metric versions aren’t as common for the older US tool brands.
USAG tools of Italy, now owned by Stanley and formerly owned by Facom, used to sell a 248 model wrench that was similar to a Check Nut wrench. USAG only made metric sizes. Depending on size needed, they sometimes turn up on eBay.
Also, there are Bicycle Wrenches that are very thin.