master Library of free plans:

"Mother of all maritime Links" Links to boat plans:

http://www.boat-links.com/linklists/boatlink-16.html#top

Small Sailing dinghies (Poland):

http://dinghy.pl/

Puddle Duck Racers (small sailboats):

http://pdracer.com/

Small Sailboats you can build:

http://www.simplicityboats.com/

Boat plans online / older plans for any style boat you can think of, large or small:

http://boatplans-online.com/

DIY Wood Boat Plans - from canoes to houseboats:

https://www.diy-wood-boat.com/free-boat-plans.html

Two Sheet Boats - mostly kayaks and cones built with 2 sheets of plywood:

http://flo-mo.weebly.com/two-sheet-boats.html

Tenders and Prams - plans for tenders and prams from Wooden Boat.com:

https://www.woodenboat.com/boat-plans-kits-categories/tenders-and-prams

Simple plywood boat plans:

http://www.plyboat.com/

Guillemot Kayaks - free kayak plans:

https://guillemot-kayaks.com/stitch-and-glue/ganymede/ganymede-offsets-free-plans-build-ganymede-kayak