Haha! I should have clarified that my laptop shown is just for meetings, travel, working remote and notes.
I had 3 monitors (all vertical) on a NVidia 750ti. I decided to add the fourth monitor early 2019 and upgraded to an AMD Radeon 570 (8GB GDDR5) to support all four monitors. The new card is performing great, much better than the 750ti. I am using 3 display ports (DP to HDMI adapters) and one HDMI port. The card is spec’d out to support six monitors (two more through one unused DVI port).
I know, it really is ridiculous! LOL! But, I love the setup. I basically compartmentalize apps to each screen. And the top monitor is great for occasionally watching a movie while I work. 
The overall cost wasn’t too bad. Each monitor (27" 1920x1080) was about $150 and the new graphics card was $160. I also built an AMD Ryzen 7 box (spent about $375) in December using the NVidia card, RAM and drives from the Dell XPS 8900 (i7-6700) box. Then, moved the previous Dell box (after adding 8GB RAM and an old laptop drive) to be a file server for my offline backup of Google Drive cloud storage and other file archives (still Windows 10). I also installed Tonido cloud to provide access to the file archives outside the office. The AMD Ryzen is much faster and more responsive than the i7 in the Dell.
I posted the AMD box specs here: What's your Budgie Machine?