Here are some nibs I have used since I started practicing calligraphy.
Gillott is my first start in calligraphy, and also my first choice for beginner. Gillott is cheap and has various flexibility. However, Gillott nib is not long lasting and can be rubbed very fast by even normal carbon ink, iron gal or walnut ink or sumi may rub it even faster.
Gillott 303: my favorite to write Copperplate, very flexible and fine. This nib is quite sharp, and easy to be bended by hard pressure. I usually use this for 3-7mm x-height, and smooth paper.
Gillott 404: nearly stiff as Nikko G, this nib is very smooth and easy to use. This nibs makes not so fine line but good for final retouched commission work. I use this for 3-5mm x-height, light weighted Copperplate.
Gillott 170: flexible and smooth, this nib cannot make fine line. This nib is very good to write on texture paper like watercolor paper.
2. Leonardt EF Principal
Super flexible, high contrast and very fine, this is my best favorite nib of all time. I use this nib for any kind of pointed pen calligraphy (Copperplate, Spencerian, Flourishing, Business Cursive), both daily practicing and teaching. I also provide LP for my students as a standard nib.
3. G nibs
Nikko G: smooth, long lasting but very stiff. Nikko G works well with even acidic ink like iron gal. However, this nib doesn’t hold ink very well and needs to be prepared carefully before use. Some kinds of ink may blob, or flow unevenly through the nib. I would recommend you to use it with pigment based ink like white ink, goache, or gold ink which are quite thick liquid.
Zebra G: the same to Nikko G but more flexible, good for beginner who wants to try Copperplate with a smooth nib.
Most Hunt nibs are quite good for medium or small writing. I love Hunt crow quill nib, it makes very thin smooth hairline.
Hunt 101: as flex as Leonard Principal but sharper and sometimes more scratchy!
Hunt 22: as flex as Gillott 404, same smoothness and stiffness
Hunt 22B: vintage nib I love most in Hunt series, a little more flexible than Hunt 22, and sharp like
Leonardt Principal. I use this nib for Spencerian.
Hunt 56: stiffer like Nikko G, flows ink very well, my favorite for small flourishing details
Hunt 99: very flexible but easy to blob
I use Easterbrook for small writing, because the nib is quite smaller than common standard, flexibility: Easterbrook 354>355>356>357>358
Easterbrook 357 is the best nib for daily practice, however, really hard to find nowadays.
6. Vintage nibs
I really LOVE Gillott Principality, smooth and super flex and super expensive. This nib is not for beginner, for penmen who master the style only.
Spencerian No.1 and No. 2: good for Spencerian, but again hard to find and very expensive.
Dao Huy Hoang
Calligraphy & Penmanship