For those who want to broaden their options and are not really constrained to only using SF2, the SFZ format has a similar purpose and there are many free instruments as they are easy to create (a text markup referring to the, typically WAV, audio files as is). Plogue sforzando [0] (freeware) is my favorite plugin for SFZ files. I learned about SFZ via an orchestra set called the Sonatina Symphonic Orchestra [1,2].

[0] https://www.plogue.com/products/sforzando.html

[1] https://sso.mattiaswestlund.net/

[2] https://musical-artifacts.com/artifacts/81?class=related-lin...