https://blackprof.deviantart.com/
This may have already been mentioned but Black Prof has an impressive gallery of great bondage art with a fair amount of super heroines.
Black Prof artwork
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Twitter https://twitter.com/mrxdbc
Deviant Art http://mrxdbc.deviantart.com/
Twitter https://twitter.com/mrxdbc
Deviant Art http://mrxdbc.deviantart.com/