niceYou can use hashtagify to find the relevant hashtags that best suits for your campaign. Also check out the Trending Hashtags in Twitter. Use Trendsmap to find the trending tags in you location.
if you need more support, we are here to help you. Google for Chilli Group.
I tried this one. It's give better result for me.all-hashtag.com is really helpful for me, have you try?