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I also vote for the Pilot Parallel pens. My instructor had me get them and they're great, easy to use, and work for most script styles except really thin cursive scripts. I recommend getting the four pack so you can have different sizes for different projects (thicker nibs are great for styles such as blackletter or just for writing larger or accenting certain words.) They are also refillable, each size uses the same ink cartridge, and you can get a variety pack of color ink to play around with. You can also get the 2.4 mm parallel pen in a pack with black & color ink. (I got both this and the four pack, I like having two 2.4 mm pens for different colors without having to switch the ink cartridges around so much.
However, if you're interested in styles such as Spencerian cursive, you would want a very thin nib that is pressure sensitive. You would probably want an oblique nib holder or a dip pen. (The thinnest parallel pen is 1.5 mm which won't allow you to get thin enough lines for Specerian or similar styles.)
For paper, high quality/thick/smooth paper is best. HP Premium 32 lbs paper is an example, but you can play around with different papers and materials (parchment is really nice to write on). But low quality printer paper (which is usually 20 lbs) is too thin and will bleed a lot.
Hello fellow FP convert! Your story reminds me of myself! I picked up a ream of this at Walmart, and it's been great for FPs, parallel pens and brush markers and it's cheap:
https://www.walmart.com/ip/Pen-Gear-Premium-Bright-Inkjet-Laser-Paper-500-Sheets/241101490
Take if from a fellow beginner and go ahead and get these two things to save yourself the headache, frustration and despair of trying to achieve with fountain pens what you can achieve much easier with cheap tools designed for the task:
1-4 pen set of Pilot Parallel pens:
PILOT Parallel Calligraphy Pen Set, 1.5 mm, 2.4 mm, 3.8 mm and 6 mm with Bonus Ink Cartridge (P9005SET) https://www.amazon.com/dp/B0141NUTUM/ref=cm_sw_r_apan_glt_fabc_S0FNWY6BDZDXKCZRSFDE?_encoding=UTF8&psc=1
2-Brush pen set:
Pentel Arts Sign Pen Touch, Fude Brush Tip, 12 Assorted Colors in Marker Stand (SES15CPC12) https://www.amazon.com/dp/B01EN0HCH6/ref=cm_sw_r_apan_glt_fabc_2MXP7SR8VTYXMYGB4TFS?_encoding=UTF8&psc=1
I wish I had known about these items the day I got hooked by the amazing talent I saw here, as most cheap fountain pens with standard nibs aren't really suited to the effects I was looking for outside of faux calligraphy.