Here is a list of small to mid sized schools in New England with D3 athletics listed by the ideas economics rankings (New England Regional and LAC)
These are ranked at the regional level in New England
MIT
Williams
Brandeis (if undergrads have free access to B-School classes)
Tufts
https://ideas.repec.org/top/top.usa-new.html
These are ranked as LACs
Wellesley (Babson can cross enroll)
Middlebury
Wesleyan
Bates
Amherst
Trinity
Colby
Bowdoin
Stonehill
https://ideas.repec.org/top/top.uslacecon.html
Here is a list by NCAA D3 tennis ranking
Bowdoin
Middlebury
Williams
Amherst
Wesleyan
Tufts
Brandeis
Bates
MIT
Colby
Trinity
Babson
Stonehill (not ranked)
https://www.ncaa.com/rankings/tennis-men/d3/regional-rankings