An internet marketers already know about the account as Ahrefs, SEMRush, WordAi, Alexa Pro, Compass Register, Majestic SEO, Instant Link Indexer. I need a reference, do you think is most appropriate must-have for SEO?
Those cost too much. You don;t need them for seo. although they do help a lot if you want to getting outranking competitors.
majestic is worth it. any successful SEO should be able to afford it. i dont find SEM rush worth it though.
I use Searchmetrics (http://www.searchmetrics.com/), Majestic SEO and few other tools. Searchmetrics is pretty good, but expensive for small businesses.
If you have 200+ keywords you want to keep checking everyday, how you are going to do that manually? How you would know the website performance?