Why can't I see my machines?

The planner only offers what your force has already researched: items, machines, recyclers, belts, modules, poles and qualities you cannot build yet are hidden, and every picker defaults to the best researched option. A modded machine appears as soon as the technology that unlocks it is researched.

To see everything anyway, enable Show unresearched options in Settings → Mod settings → Per player. It is a per-player setting, so it changes the lists only for you.