Useful Links... I mean really useful

IB chemistry topical PPQs (SL and HL)
https://sites.google.com/a/nisbah.com/chemistry/IBDP-Chemistry/dp-chemistry

IB physics topical PPQs and past papers (SL and HL)
http://nothingnerdy.wikispaces.com/IB+PHYSICS+REVISION

IB physics topical PPQs
https://thisisphysics.wikispaces.com/IB+PHYSICS+REVISION

IB economics sample essays and examiner comments
http://xmltwo.ibo.org/publications/DP/Group3/d_3_econo_tsm_1102_1/html/67.207.142.65/exist/rest/app/tsm.xql@doc=d_3_econo_tsm_1102_1_e&part=1&chapter=1.html

IB English poetry and play analysis (made by my senior Matthew)
http://matthewspoetryanalysis.blogspot.sg

I used to look for IB maths HL past papers on Diamond Bar High School's website, unfortunately they removed it due to copyright issues. :( If you know where to find please comment below. Thanks.