Notices of American Mathematical Society

https://goo.gl/XVvXTz

Or generally (just replace the 201603 with yyyymm):

http://www.ams.org/journals/notices/201603/201603-full-issue.pdf

Or this URL as well:

http://www.ams.org/notices/201502/201502-full-issue.pdf

Polish Mathematical Olympiad 2016/17 - Mathematics Meta Stack Exchange

https://math.meta.stackexchange.com/questions/25020/polish-mathematical-olympiad-2016-17?rq=1

SIAM: Math Matters, Apply It!

https://www.siam.org/careers/matters.php

Try these problems from historical Tripos

A trip into Mathematical Tripos through its history

Looking at this:

http://maths-obsession.blogspot.sg/2015/05/searching-for-mathematical-tripos.html

Many links are outdated, so perhaps here are some updated links:

https://www.maths.cam.ac.uk/undergrad/pastpapers

And these are the pre-1878 era:

https://www.ocf.berkeley.edu/~lekheng/tripos/math-tripos-pre1878.pdf

And lots of others:

https://www.ocf.berkeley.edu/~lekheng/tripos/

https://tartarus.org/gareth/maths/tripos/

https://www.maths.cam.ac.uk/past-examination-papers

https://www.maths.cam.ac.uk/undergradnst/pastpapers

Good Olympics Questions (Computing)

http://wcipeg.com/problems   (from China)

https://noi.ph/past-problems/  (Phillipines)

https://github.com/ranaldmiao/sg_noi_archive (singapore)

http://codeforces.com/problemset

Putnam problems

https://web.archive.org/web/20080124125203/www.kalva.demon.co.uk/putnam.html