Austria/Germany have gray for 16A Diazed!
There are quite a few ways of overfusing a Diazed circuit. Removing the key at the bottom of the element is only one. others are: Open the burnt fuse and replace the fuse wire with a paper clip. Wrap a single strand from an old extension cord around the outside of the fuse. (I saw my uncle doing that about 8 years ago when a fuse blew and he didn't have a spare one).
When we moved into our new appartment there were 2 circuits which should have been 6A, or 10A with grinded teeth. One set of fuses (hot&neutral) had the key rings removed, the other set replaced with grey 16A ones. I assume originally there were ocre 4A ones.
Pink 2A ones never really caught or have long since disappeared.
25A is yellow (commonly used for pre-meter fuses, either 2x25A (appartment single phase feed) or 3x25A (3ph, in most cases because an electric range is used), some older appartments are even on 2x20A (for example our 100m2 appartment in rather luxurious area of Vienna, house built in 1913, wiring part original, service and risers to the pre-meter fuses on each floor have been replaced during the switchover from 127/220V 3ph w/o neutral to 220/380V in the 60ies or 70ies, back then the house with 8 appartments of more or less the same size got a new 60A 3ph service). Lots of gas, coal and wood heating here, AFAIK about 3/4 of the households here are cooking with gas, heating even more)
