ResFool

ResFool is a resource editor that supports full ResEdit template support. Use one of the 100 included templates to edit existing resource types. If those aren't enough for you, you can construct your own using 94 template types, or use one made by other people in the active Mac developer community. The possibilities for editing binary data in a semantically enriched environment are endless. With support for nested lists, skip fields, arbitrarily aligned data, strings, numerics and more, ResFool templates allow for editing a diverse range of data.
ResFool also comes with several custom editors. There is an editor Apple Event terminologies ('aete'), Pascal string lists ('str#'), styled text ('TEXT' with an optional 'styl') and versions ('vers').