basefont, big, center, font, strike, tt, u
CSS does all of this now. These tags just clutter up your page. They provide no semantic value to your app.

iframe, frameset, noframes
These tags damage usability, accessibility, SEO, etc.

table
Table is for tabular data only!

Remember: HTML5 features are all client-side and subject to security issues. Double-check all user uploaded-data on the server!

(Source: http://html5tutorial.info)