I've been using PostBuilder (used to be called gramspacer) for several months now and I use it almost every single work day. PostBuilder makes it super convenient for organizing and planning content for my Instagram pages and the founder is very responsive if you have questions or if there's ever an issue. I definitely recommend them!
Caption This - Create a smart caption for your photo in a second!
Drake Shake - Shake to add Drake to any photo
Quik by GoPro - Easiest way to create awesome videos
PicMerger - Merge photos side by side, create beautiful photo collages, customize your content with built-in photo editing tools, and more
MotionDen - Free online animated video maker
Instagram Line Break - Simple clean line breaks for your Instagram captions