Only these three are most probably fonts, the rest is handwritten. The only thing I can tell you is that the hearts are probably MWHeart font.
Scanlation Thread
Gavin Baker
John Young
So how are these generally made? some sort of drawing tablet?
Alexander Torres
It's pretty much as simple as getting a decent drawing tablet (I've been using the same old Wacom Bamboo for over a decade) and drawing them on some layer in PS or CSP. Depending on how small your RAWs are, you may also want to apply a sharpen filter or go over with the sharpen tool by hand, because PS AA for their brushes is stupidly blurry.
Some FAKKU manga letterer made a tutorial for making your own font if you're interested in that.
youtube.com
Another manga letterer made their own donationware brushes recently (they have default mode set to dissolve, so you may want to set it to normal, but up2u).
gumroad.com
Wyatt Robinson
could you get by with drawing on paper and scanning in?
Aaron Ramirez
Thanks for the links. I'm using a Huion H950P which is also pretty solid for the price.
I don't see why not. It's more work, but might even look better in the end if you know what you're doing.
On a related note, is there a simple way in PS to achieve something similar to the Isolate Lineart plugin in PaintNet (making all white transparent, including gradients)?