The system supports a wide variety of encodings. If you want UTF-8 tell the system you want that data encoded using CCSID 1208. If you want Latin 1 EBCDIC tell the system you want that data encoded using CCSID 37 (US/Canada), 273 (Germany/Austria), 278 (Finland/Sweden), 500 (Multinational), or several others. If you want Latin 1 ASCII tell the system you want that data encoded using CCSID 819 (ISO/ANSI Multilingual) or 1252 (WIndows). The same type of thing can be done for Latin 2, Cyrillic, Greek, Chinese, Korean, etc. For Unicode, in addition to UTF-8, there is also 13488 for UCS2, 1200 for UTF-16, etc.
One nice thing about the system is that you can have all of these CCSIDs active at the same time. You could even have one table (or file) with some columns (fields) in CCSID 37, other columns in 1208, and yet other columns in 1200. Likewise you could have some IFS stream files in 37, others in 1208, others in Cyrillic (1158), etc.
So the answer to your question is “lots”. The system does not force one encoding on to your databases.