Whitehat links. or rather links that Google doesn't seem to mind right now.
Links related to your website subject.
Links related to your location.
PAD links from quality software directories.
Links from pod cast sites where content is made available.
Link from document sharing websites where content is made available.
Links from image sharing sites where content is made available.
Links from video sharing sites where content is made available.
Resource links from Wikipedia.
Contextual links from sites related to your business or location.
Links from suppliers and business associates.
Contribution links from charities. (Search for "sponsor us" and pick high value sites to support, especially if they are related to your niche. Sponsoring a "Gro your MO" website makes sense if your site is about prostate cancer.)
Social Media sites that share your information will result in some links.
Profile links from social media sites you rally use (Linkedin, Twitter, Facebook comes to mind here)
Some link bait that seems to be working:
Infographics, if they're well done
Software related to the niche for PAD submissions.
Top 10 posts. infographics, or lists.
If you have a sewing machine site, list the 10 best sewing machine sites for your readers, sent these sites a notice that they have been chosen, many times they will link to your post to publicize the fact.)
Surveys
Articles published on other authority websites.
This is contextual links, but do not think only blogs here. If you have an eco friendly product, write an article casually mentioning it along with a few other products ("the top 5 products for reducing household waste" or something) and submit it to an ecology themed site. Often they will print it.
I am not sharing the exact method, but occasionally you can find pages on the web that let you resister to post on someone else's network. Many times these are .edu domains. Find these pages, register as a contributor, and you can post to the .edu site setting up your on contextual links in your postings. I never post more than a 3 to one ratio of SEO posts in these cases, they will remove the account if anyone complains.
I am not sharing the way to find these, so don't ask. I don't want to ruin a good resource. It's there if you can ferret them out.
Keep in mind that any link you build today may have to be disavowed in the future.
Last little bit: Ads are links too. Contact smaller but mid PR websites and offer a token amount for a one year text ad on the home page. Insist on do follow.
I have a PR 5 tech site and I sell ads at the bottom of the home page for $30 a month. I show only 3 ads, and they say something like "XXX is sponsored by XXX".
Before I knew their value, I sold them for $25 a year.