DEIM

Discrete empirical interpolation as introduced here (super simple):
https://ieeexplore.ieee.org/abstract/document/5400045

Absolutely critical to make POD based MOR techniques actually useful in strongly nonlinear (not polynomial) settings. 

Here is a very crude idea for enabling DEIM with minimal intrusion by incorporating symbolics into the pipeline.
https://github.com/FHoltorf/DEIM.jl