What are some words with an English and American spelling?

You're asking about words with different spellings in British English (BrE) and American English (AmE). Here are some examples:

-or vs. -our:

* BrE: colour, humour, favour

* AmE: color, humor, favor

-re vs. -er:

* BrE: centre, theatre, metre

* AmE: center, theater, meter

-ise vs. -ize:

* BrE: realise, organise, analyse

* AmE: realize, organize, analyze

Other differences:

* BrE: tyre, licence, programme

* AmE: tire, license, program

Note: There are many more words with different spellings in BrE and AmE. These are just a few common examples. It's important to remember that both spellings are considered correct within their respective dialects.