Get inspired at Thingiverse https://www.thingiverse.com/
Design your 3D print job at TinkerCad https://www.tinkercad.com/#/ or Google SketchUp https://www.sketchup.com/. Make sure you use your Google Education account to sign in!
Print an Edison robot pen holder here https://www.thingiverse.com/thing:2949946
Convert 2D drawing to 3D here https://www.selva3d.com/ or https://picsvg.com/ (Picsvg better)
STEMshare online 3D printing resources are a great option! Find them here https://schoolsnsw.sharepoint.com/sites/IE70HV2U/SitePages/3D-Printing.aspx
Lesson Plans using 3D printing can be found here https://www.thingiverse.com/education and here https://www.instructables.com/howto/snowflake+3D+print/
STEMshare SuperHero Unit plan https://schoolsnsw.sharepoint.com/sites/791PKB5I/superhero/SitePages/Home.aspx