Looking at https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git/tree/mkfs/f2fs_format_main.c, the definition of parse_feature is taken from the file include/f2fs_fs.h. This function uses a table with 10 feature names (not all make sense for normal users!): https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git/tree/include/f2fs_fs.h#n1361:
encrypt
extra_attr
project_quota
inode_checksum
flexible_inline_xattr
quota
inode_crtime
lost_found
verity
sb_checksum
