None.
Sorry.
There are NO MORE good third party, smart Bluettoth stylii for older iPads, any longer.
Since Apple stopped supporting these older iPads, many accessory manufacturers have also quit makng things that work with older iPads, as well, and this includes oldr, smart Bluetooth stylii that were competitors for the original Apple Pencil 1.
Adonit did one more shipping round of the Pixel back in March 2020 just before the CO-vid quarantine, but has seemed to have desisted from continuing to produce this older stylus any longer.
There are NO smart, Bluetooth stylii for ANY older iPad models any longer!
Many third party smart stylii makers stopped making these for older iPad models that are non-Apple Pencil compatible.
Sorry.
Your only options, today, are the easy to obtain/purchase fatter tipped, commonplace, capacitive stylii on the market
OR
capacitive stylii that use a clear disc tip ( the clear disc tipped ones are more accurate for writing or drawing ), but with the clear disc type of stylii, you should look for one that has a disc that is made from a clear, flexible material that will minimise any type of scratching should any type of grit or dirt gets on the tip.
(This little tidbit of warning applies to ALL stylus types as all can scratch your iPad’s screen if dirt and grit are allowed to drag on a stylus tip across the iPad's screen ).
OR
The so-called, fine tipped “Active”, battery powered ( most times rechargeable battery powered ) capacitive stylii, like many found on Amazon.
These fine tipped, “Active” stylii use a battery to send a tiny electrical current to the fine tip of these stylii that simulates an actual finger touch to the iPad's screen.
These types of stylii are not the greatest and many of these produce varying degrees of noticeable line jitter when drawing any type of angular lines.
Some of these “Active“ stylii do a better job at minimising this angular line jitter than others, but I have no idea which ones do minimise this better, so if searching for one of these on Amazon, you will need to read the reviews.
Also, still need to make sure that these “Active” battery powered stylii are compatible with your IPad model.
Some of these, especially new to market ones, are NOT!
All of these these types of stylii work with all sketching/drawing/painting/writing apps, but without any palm rejection and/or screen pressure features.
You can use this stylus with other apps but will not be able to lay your palm on the screen, while you write or draw, unless you use special, non-body electrical conducting, lycra-based material drawing glove that works by isolating your hand/palm electrical impulses from the iPad's screen and allowing you to lay your hand/palm on the screen as you draw or write.
Something like this found on Amazon.
https://www.amazon.com/Professional-Anti-fouling-Drawing-Tablet-Graphic-Right-Ha nd-Left-Hand/dp/B017R8M2JY/ref=sr_1_1_sspa?ie=UTF8&qid=1543548123&sr=8-1-spons&k eywords=lycra+drawing+gloves&psc=1
Many more makers of these types of gloves found on Amazon and in different hand sizes and limited colors, as well!
Best of Luck to You
