While there isn't a limit to the number of anchors or jump links you can have, know that the more text formatting (links, colors, fonts, etc.) you've applied to an email campaign, the heavier that campaign is going to be because it builds up the HTML.
Our proofer will alert you if your email is over 40 KB. Typically, anything under 60 KB is OK, but lighter is always going to be better in terms of delivery, so I wouldn't go too nuts with the links. There isn't a magic number, but I'd aim to create fewer than 10 anchors in your email -- And I'm determining that number based on my own experience as an email recipient, and I'm not as likely to interact with 10+ anchors in an email. It can get a bit old. :) But I'm open to your feedback and creativity!