There are more than 20 software available for filing GST returns and for other compliance.
But before answering you, of which I am not certain as of now.
First we should ask, whether you really need a software to file your GST return.
GST portal in itself is a strong and well managed application which you can use to file your returns.
I do not recommend any software for filing your monthly returns.
Just download return filing utility from GST portal and use it. It will not only save cost but reduce your dependency on any third party software.
I will further review each and every software and update this answer. If I really like a particular software, will give my genuine opinion on it.
Check another thread on same topic List of best software for GST returns