So this is my attempt at searching key sub-ranges. If you know the key begins with 0x20 then I was searching for "13zb" and keys that printed 0x20-0x3f are noted. I went through various puzzles, some already solved and broke the key ranges down into sub-ranges. Hopefully you will find this useful.

import multiprocessing
import base58
import secrets
from bitcoin import privtopub, pubtoaddr

def vint():
    puzzle_66 = "13zb1hQbWVsc2S7ZTZnP2G4undNNpdh5so"
    btc = ""

    while btc[:len(puzzle_66)] != puzzle_66:
        alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
        untext = "".join(secrets.choice(alphabet) for i in range (12))
        text = '11111111111111111111111' + 'C' + untext                  #23 1's  'C' is the parameter you can change.
        base58Str = base58.b58decode(text).hex()
        pubKey = privtopub(base58Str)
        btc = pubtoaddr(pubKey)

    f = open("keys.txt", "a")
    f.write(base58Str + "\n")
    f.close()
    b = open("btc.txt", "a")
    b.write(btc + "\n")
    b.close()

    print(base58Str)
    print(pubKey)
    print(btc)

processes = []
for _ in range(1):
    p1 = multiprocessing.Process(target=vint)
    p1.start()
    processes.append(p1)
for process in processes:
    process.join()

LINK to text files with key sub-ranges.
https://drive.google.com/drive/folders/176gIM6ACTyZg5Ux5Adsu-kP5S3LspLcU?usp=drive_link