HASHTAG AGGREGATORS
These apps will aggregate hashtags for you by vertical/industry for use on Instagram.
Focalmark
Focalmark uses human research plus a ranking algorithm to suggest hashtags that connect your photography to a real audience. This mix of human and machine means the suggestions are both relevant and increase exposure.
Free
HashTags App
HashTags For Likes is an app to help increase likes and followers for your Instagram account by providing your with top hashtags to utilize on your posts.
Free
Smarthash
Smarthash is the only app that enables you to Split Test your hashtags on Instagram to give you an accurate picture of which hashtags are actually influencing more engagement.
Free, in-app purchases available