Support for making standalone type libraries is planned but not yet implemented. Of course,, twinBASIC imposes none of the artificial limitations of VB6 on number of code elements. If your project isn't working in tB, outside of internals hacks it's easy to replace, it's usually only one or a handful of bugs, and working to isolate and preferably make minimal reproductions would see them fixed fairly soon if blocking something from working entirely.

The best option assuming you're not planning on bringing the full project into tB, as previously mentioned, is mktyplib, a utility included with VB6. Between oleexp, OLEGuids, and The trick's various tlbs, it's not hard to find ready made examples of making typelibs.

Note that as written, your typelib will be subject to full activex registration requirements and will exhibit problems if you don't unregister before overwriting old versions. This is due to use of uuid-associated types. There's some uses, namely being able to avoid the 'only public types in public modules blah blah blah' error, but oleexp forgoes them for the ease of no registration headaches. Just the types and enums, no uuid or version attribute on them.