The first kind, of course, include also the ink bottles you mean, because internal conical shape has internal ink well due of that internal shape. Also MB for example needs a turning when you finish the ink in the little inkwell inside. So I summed all internal inkwells and internal conical shapes in one category because they both can permit to use nearly the last drop.

Edited to correct some typos.

I am pretty sure it was not economically feasable to tool up t make the inkwell bottle. The things are so well liked I am quite sure that if anyone could get a reasonable return on the setting up cost they would have done it by now.

Mr. Tardiff has a famous (for us) statement on why Noodlers had to end up in the bottles he uses so it could meet the target price point.

I inserted levenger on the list but I used only internet images and those that not explain the internal shape. So if you have a Levenger ink bottle, can you show us the internal? If the little inkwell is on the center of the base, I think it is nearly impossible to use the last drop if around there is a little climb around it. If there is not, sorry but from the pics I saw it seems to be there.

Yes you are true that all bottles can be tipped to a angle but not so convenient in the "blind zones" category because of the bottom angle that is not reached from a pen inserted. Try with Pelikan 30ml There is a little part of that internal angle impossible to reach. Same with indentical or similar bottles. In other bottles, the new based area could be too large and it loose the possibility to be used as an internal inkwell (Aurora). In other again there is no other possibility except you want to try the angles putting the bottle in a particular and dangerous equilibrium (Private Reserve).

Waterman and OMAS have not this blind angle.

Anyway, best solution is the travelling ink pot and with this idea I cannot understand why a producer don't put a rubber ring around the internal neck to use every bottle like a Visconti travelling ink pot.

The mechanism is simple: if the pen cannot reach the last drop, let the last drop go to the pen. if you turn upside down the bottle with a proper ring internal to the bottle neck and a pen with the nib safetly and ermetically inserted, you can aspire all the ink in the pen, just because the base of the feed can be putted at the same level of the rubber.

As with Visconti travelling inkpot of course it is better to apply with the last drops only because air dilatation is simple than ink dilatation and the piston has not to be force dangerously to this way.

I'm afraid the only Levenger bottle I have is filled with dark brown ink and wouldn't photograph well at the moment. The gimmick, though, is a small plastic reservoir, enough for one or two fills, that hangs from the rim of the bottle, with slits near the top that allow the reservoir to fill up when the (capped) bottle is upended. You insert the nib into the reservoir to fill. Truth be told, I don't know how well it works when the bottle is nearly empty. But it's a comfy way to fill a pen because it removes the worry of ramming the point of the nib against the bottom of the bottle; the reservoir, which is made of a soft plastic, acts as a cushion. I hope that gives you something of a picture.

Uhm...
The Parker bottle I mean in the poll was the Parker Quink... not the Penman that I have never seen also online...

I agree. The MB bottles are super steady, have a convenient shape, high quality cap, and are simply beautiful to behold. I like the side "V" chamber, versus the more common central one (like on Lamy bottles). I've only used their Blue and Black inks and find them quite good. The black seems to have decent water resistance, though I suspect less permanent than Noodler's Eternal and Bulletproof inks.

Blind zones shapes are that bottles with an uncovered angle also putting the pen and the nib in different positions u cannot reach the last little amount of ink. Tipical are Pelikan 30ml shapes, which seem to have no blind zones but if you try, you cannot fill the pen with the last amount because the nib cannot reach it.

Instead for the Pelikan India I have never seen it, and also I don't know anyone that can describe it so you can consider it as Cylindrical shape, also because as you said, you cannot use the last drops of ink.