Throughout my needs as a designer in both context of academic and professional, there are just times when we need to scourge for free but quality resources. Thankfully for the internet, we have a couple of well-hidden free (or at least free-ish) resource sites which I'll cut to the the chase and recommend below:
Mockingbot - Wireframing Tool (Cloud-based)
If you're in need to deliver mock-ups quickly and hassle free, MockingBot is definitely the way to go (or at least in my opinion for the many resources I'm going to list). It may not be as robust as the popular InvisionApp or the recent Adobe eXperience Design but it definitely offers the basic with a really low learning curve. It can do up wireframes, create simple interaction and transitions in a jiffy. It even shows you an overall interaction map of all your wireframes altogether. If required, the pricing plans are definitely looking economical if you need more storage and co-workers working on the same wireframes.
2Dimensions Nima - 2D Rigging and Animation (Cloud-based)
A recent find and still in beta. I may not be much of doing 2D animations but this is really worth a check. They seem to rock a really clean UX for an animation pipeline: bone-based, inverse kinematics, weight painting and animation-curves workflow. All your works will be done in the cloud and can be showcased via their gallery, kinda also serving as a portfolio for professional 2D animators out there. This definitely places competition for similar installation-based software such as Spine or Live2D with a price tag on them.
Sonniss GDC Audio Bundle (20GB+)
Sonniss has been doing this for 3 years straight with bundles from 2016 and 2015 respectively. You gotta request for the 2015 download links since they have taken it down. There's gotta be enough content in these bundles for much of what any small to medium scale games might need (with a little of mixing and editing of course).
Texture Ninja (Free Textures)
Many people often struggle with finding 3D textures with simple Google (they just don't turn up without watermarks yea?). This is one of the sites that offers quite a bunch of realistic textures commonly needed: materials, doors, signages, etc. Support the patreon if you might benefit from a fuller list of textures.
This marks the end of my first resource post. Do share these resources to many fellow devlings that might have a need for them. Bon Appetit!