I really like IBM's Business Conduct Guidelines [1]. I think they help to creat a culture of doing things "above board" which can avoid some major motivation killers.

Bayond that, I enjoy quite a lot of autonomy in deciding how I complete my work, and often even what work I perform. Starting a new project that I want to do is obviously more motivating than one I don't care about.

Code reviews help me stay motivated to write code that I'll be proud of rather than cheap hacks. Open Source work is kind of an extension of this.

I know you asked for "other than pay" but unexpected bonuses and raises are also nice motivation boosters in my experience.

[1]: http://www.ibm.com/investor/att/pdf/BCG_C_2016.pdf (PDF)