Free sweater pattern generators:
Knittingfool: http://www.knittingfool.com/Pages/Sweaters.aspx
Percentage method for drop sleeve gansey, top-down raglan, and set in sleeve pullover. Have used set in sleeve pullover with success.
raglan sweater generator: https://colinrmitchell.com/knitting/raglan.php
Bikibird pattern drafting: http://knitting.bikibird.com/patternDrafting.html
pull-over, cardigan and poncho generator with lots of room for alterations
The knitting fiend: http://www.thedietdiary.com/knittingfiend/OrderForms/TopForm.html
also a yoke sweater generator: http://www.thedietdiary.com/blog/lucia/1823
Very detailed options, which makes it a bit complicated
Aiguilles magiques: spreadsheet for a basic sweater https://www.aiguilles-magiques.com/Calculation-for-an-adult-sweater?lang=en
Woolmi: https://woolmi.app/step1 (thanks @hearteyedraccoon for the tip!)
Lindy's knits and laces: pullover spreadsheet http://www.lindysknitslaces.com/2010/04/24/knitting/designing-a-sweater-without-a-pattern/
I have been looking for this one for ages - also used it once upon a time, then lost the source.
Bellish also got recced, and I have the app, but the website has closed down.