The real problem is it seems this has been happening awhile and you haven't caught on until the traffic drop trigger right? So lesson learned to keep an eye out.
Have you seen a rise in rankings over the last year, then a drop? The reason I ask is because some of the links on some of those domains might be helping you and any action on your part could cause a drop in rankings no matter what you do.
Example: oletravel.net w/ 125k backlinks to you is offline, your rankings are down, they could have been helping you.
I asked about the patterns in their links to you for a reason, you have certain options if their link patterns contain non existent subdirectories on your site, if they're really serious/or knowledgeable about damaging you this will be the case.
If you're worried about server load get cloudflare and use their custom 404 page option and add your home page code there or a nice keyword rich link to your homepage.
Disavow the domains, not individual urls, and send to Google ASAP
domain:oletravel.net
domain:hystoretechnologies.com
Disavowing a full domain goes through quick, a couple weeks or less, and enough submissions from others and Google penalized the bad domain, that's why Nico-T says not to report! (JK
).
There are tons of other options and someone will always disagree or have a better way but if you're stressed and are low on server resources follow what I said above as your first steps
.
*Posted from my phone