There's no need to have 10 to 20. My idea would be 2-3 non-combat retainers (like the Noble feature) and 1 ''pick from two'' companion, like the beastmaster. At high level, say 11+.
Example:
Companions
At Xth level, when you finish a long rest in a settlement, you can have a small band of daring initiates ask to join your cause.
They are friendly to you and your companions, and obey your commands. You determine the creatures appearance; your choice has no effect on its game statistics.
You have the service of four retainers. These retainers can be attendants or messengers, and one might be a majordomo. One of your retainers is a Companion who serves at your side in combat, aiding you in exchange for training on his or her own path to fame. See this creature's game statistics in the Companion stat block. Your three remaining retainers might include a groom to care for your horse or a servant who polishes your armor (and even helps you put it on). All retainers but your Companion can perform mundane tasks for you, but they do not fight for you, will not follow you into obviously dangerous areas (such as dungeons), and will leave if they are frequently endangered or abused.
In combat, the Companion shares your initiative count, but it takes its turn immediately after yours. It can move and use its reaction on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it to take one of the actions in its stat block or the Dash, Disengage, Help, Hide, or Search action.
The companion follows the same dying rules as a normal character. If it has died within the last hour, you can use a healer's kit as an action to revive it, provided you are within 5 feet of it and succeed on a DC 15 Wis (Medicine) check. The Companion returns to life after 1 minute with all its hit points restored.
At the end of a long rest in a settlement, you can recruit a new retainer or companion unless you already have three retainers and a companion.
STR | DEX | CON | INT | WIS | CHA | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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Medium humanoid, neutral | | | | | | | | | | | | Armor Class 15 (chain shirt) | | | | | | Hit Points equal the companion's Constitution modifier + your Intelligence OR charisma modifier + five times your level in this class | | | | | | Speed 40 ft. | | | | | | | | | | | | 14 (+2) | 12 (+1) | 14 (+2) | 4 (-3) | 10 (+0) | 6 (-2) | | | | | | | Saving Throws Dex +3, Con +4 | | | | | | Skills Athletics +4, Perception +4 | | | | | | Damage Immunities | | | | | | Condition Immunities charmed, exhaustion | | | | | | Senses , passive Perception 14 | | | | | | Languages understands the languages you speak | | | | | | | | | | | | | | | | | | Might of the Master.
The following numbers increase by 1 when your proficiency bonus increases by 1: the companion skill and saving throw bonuses (above), the bonuses to hit and damage of its rend attack, and the number of hit points restored by its first aid action (below).
Vigilant.
The companion can't be surprised. | | | | | | Actions (Requires Your Bonus Action) | | | | | | Longsword.
Melee Weapon Attack: +4 to hit, reach 5 ft., one target you can see. Hit: 1d8 + 2 slashing damage.
First Aid (3/Day).
The companion restore 2d8 + 2 hit points to itself or to one ally within 5 feet of it. | | | | | | Reactions | | | | | | Deflect Attack.
The companion imposes disadvantage on the attack roll of one creature it can see that is within 5 feet of it, provided the attack roll is against a creature other than the defender. | | | | | |