Love, war, death, nature, religion, friendships… This website categorizes poems that are mostly by British Poets. Check this out first.
http://www.love-poems.me.uk/
British War Poetry
http://www.fordham.edu/halsall/mod/1914warpoets.html
Shakespeare's sonnets, or simply The Sonnets, is a collection of poems in sonnet form written by William Shakespeare that deal with such themes as love, beauty, politics, and mortality http://en.wikipedia.org/wiki/Shakespeare's_sonnets
The Sonnets of Great Britain
http://www.sonnets.org/