Not including special event callsigns, which group (country/class/etc) of hams have and use the longest callsigns?
I know that theoretically the longest would be a (3x4) or 8 character callsign but are these in use? I’m interested in which countries in actual practice issue incredibly long callsigns to individuals.
Several nations have special event stations with call signs longer than normal. I know of one nation which issues 3-character prefixes (Eswatini), but those are all 3x2 call signs (3DAnxx). Australia until recently issued 2x4 calls (VKnFxxx) but stopped a little while ago. The USA once issued multiple number calls for special events IE W100AW. The longest I know of would have to be the STAYHOME call signs IE OH2STAYHOME which would be a 2x8 call sign, but are special events. Portable call signs such as VK6Fxxx/3DA0 could be a long call sign, but isn't issued per se. If that counts, a state QSO party call such as AI7OW/KITSAP would also qualify.
UPDATE: Guinea issues 3x1 call signs along with 2x1 and 2x2, 3XYn?