Non-extendable 2D TQFTs correspond to finite dimensional Frobenius algebras [1].
How about 3D TQFTs? While the answer is clear for the extended ones (e.g. (3,2,1) TQFTs almost correspond to modular tensor categories [2]), I have not seen any discussion for (3,2) TQFTs.
More precisely, can one classify the functors
$$Cob_{3,2}^{oriented} \to (Vect_\mathbb{C})?$$
Reference
- [1] Cohomology rings and 2D TQFTs
- [2] K. Walker's answer here
- [3] related - Example of a non-extendable TQFT?