What's a good replacement for a Deore LX 3x10 front derailleur?
Almost any Shimano 3x10 MTB Derailleur, but Deore FD-M6000 is a good match for what you have now.
Be careful that you match the clamp band type and that you get the correct down pull / top pull version to match your current one.
Down pull is where the cable rises from the bottom bracket.
https://bike.shimano.com/en-US/product/component/deore-m6000/FD-M6000-M.html
Or
https://bike.shimano.com/en-EU/product/component/deore-m6000/FD-M6000-H.html