The D&D 5e Homebrew Tumblr page has a ton of really nice material for a D&D 5 game. Including a lot of monsters.
The pages are well done and there is a lot of material here.
Including some new dragons:
It's fun blog and worth your time if you play D&D5 at all.
Don't forget to include the hashtag #MonsterMonday on Twitter or #MonsterMonday on Google+ when you post your own monsters!