Grammarly
Grammarly Blog: I Before E Except After C: 9 Helpful Spelling Rules
This site provides nine important spelling rules and examples. L.9-10.2c Spelling, L.11-12.2 Cap/Punc/Spell
Other
Spelling Rules: Words Ending in Y
Chart with rules and examples for adding suffixes to words that end in -y.
BBC
Bbc: Skillswise: Suffix Spelling Rules: Double Letters [Pdf]
Learn when to double the final consonant of a word when adding a suffix, and when the consonant does not get doubled.
Grammarly
Grammarly Blog: Hyphen With Suffix Elect
Rules and examples for using a hyphen when adding the suffix -elect.
Other
Oxford Dictionaries: Words Ending in Sion, Tion, and Cion
Learn the spelling rules involving when to use an "s," "t," or "c" when adding an "ion" suffix.