Not every new Magic: The Gathering mechanic is kicker. Some are multi-kicker. Or horsemanship.
Magic: The Gathering players aren't too far off when they joke that 'everything's just kicker.' Kicker debuted in 2000's Invasion set, and has since been subject to comparison with any new mechanic that allows you to pay extra mana for a better effect.
Head Designer Mark Rosewater has since called the mechanic "too all-encompassing," claiming it was a mistake to design kicker so generically. Even some kicker-lite abilities alter how and when you can pay extra mana, and some reverse the play pattern by allowing you to pay less mana for a weaker effect.
10 Entwine And Escalate
Entwine and escalate are near-identical kicker mechanics found on modal spells. Entwine was originally used to combine the effects of cards with only two modes, whereas escalate allows you to pay an additional cost multiple times to keep adding modes. Escalate spells with only two modes work exactly the same as entwine spells.
Entwine has been used more recently despite escalate being the newer mechanic. Kaya's Guile in Modern Horizons demonstrated that a single entwine payment could cover multiple modes at once, and that escalate was pretty much unnecessary.
9 Adapt And Monstrosity
The Simic guild's adapt mechanic, and the more generic monstrosity ability, are 'delayed' kicker variants that exist as mana sinks you can pay later to make a creature more powerful. They're virtually the same mechanic, with adapt being reusable if the creature somehow loses its +1/+1 counters.
Players mostly associate kicker costs with additional payments upon casting a spell, but just about any 'more mana more power' design fits the bill. Adapt and monstrosity allow you to pay in installments, which is usually better than having to pay the full cost all at once.
8 Overload
Overload is kicker through and through, the unique part being that the alternative cost actually changes the text of the card. Overload spells are a bit harder to design than normal kicker spells, since the mechanic only works on targeted spells, and the effect has to be something worth spreading out to multiple targets.
This ability does lend itself to some unique and clever card designs, such as Mind Rake, which actually has a cheaper overload cost with a generally worse effect, and Damn, which uses an off-color overload cost to differentiate the types of decks it's viable in.
7 Morph
Morph, and by extension megamorph, is an interesting and strategically rich form of kicker. It's a hidden information mechanic that uses the element of surprise to catch players off guard while splitting the payment up across different turns.
You can cast a morph card face-down for three mana, you can cast it face up as normal, or you can cast it face-down and 'kick' it for its morph cost right away for an immediate effect. And of course, morph cards disguise one another and play naturally well together. The morph the merrier!
6 Squad And Replicate
As if kicker wasn't already ubiquitous enough, 2010's Worldwake introduced multi-kicker, which covers just about anything that allows you to pay an extra cost multiple times for a scaling effect. Squad and replicate fall under this umbrella, turning extra mana into extra copies.
Squad is linked to the Warhammer 40k Commander decks and only works on creature spells, creating extra token copies if you pay the squad cost. Replicate used to be tied directly to instants and sorceries, but has since branched out to permanent spells with the addition of Threefold Signal and Hatchery Sliver.
5 Prototype And Evoke
Some mechanics aren't content being kicker, so they reverse the formula. Most prototype and evoke creatures have the more expensive version on their front end, but offer a less powerful version as a cheaper alternative. As it turns out, 'reverse kicker' is still kicker, since they still basically offer a stronger version for more mana.
Evoke cards have more diversity to them, with variable alternate costs that aren't always cheaper than the original casting cost. The Modern Horizons 2 'pitch elementals' are frequently cast for their evoke costs, and you might consider hard-casting one the 'kicked' version.
4 Buyback
Buyback's about as kickery as they come. It's the bear-bones design philosophy of spending extra mana for a bonus effect, in this case returning the buyback spell to the owner's hand. A buyback spell could very easily be rewritten with kicker instead, with rules text that returns the spell to hand after resolving if the kicker cost was paid.
Much like multi-kicker spells, buyback cards often serve as infinite mana sinks that can win games on the spot. Brush with Death and Searing Touch are examples that do a great Comet Storm impression by converting infinite mana into wins.
3 Extort
Extort only exists on permanents, but it's just a tangential way of granting a kicker ability to your other spells. As long as you control a permanent with extort, each spell you cast comes custom-fitted with a 'kicker' cost of an extra mana for a one-time life drain effect.
Multiple instances of extort on the battlefield are the functional equivalent of giving all of your spells multi-kicker instead. Permanents you control with extort stack, adding further optional mana payments to your spells for bonus drain effects.
2 Casualty
Not all kicker costs have to take the form of extra mana payments. In the case of casualty, the added cost is a sacrificed creature within a certain power bracket, and the reward is a copy of the casualty spell. It's a slight twist on the kicker blueprint, and one that encourages a different deckbuilding approach overall.
Casualty spells sit at the crossroads between spellslinger decks and creature decks, encouraging you to play expendable creatures instead of simply producing extra mana. It's interesting territory, and gives blue decks a more prevalent sacrifice identity.
1 Strive
You know the whole "Superman and Clark Kent in the same room together" joke? That's strive and multi-kicker in a nutshell. Strive allows you to pay a predetermined cost multiple times when casting a spell to increase the number of targets. Sound familiar?
Like overload, strive has fairly narrow design space since it can only exist on targeted spells with effects worth amplifying in the first place. It's not as all-or-nothing as overload though, allowing you to adjust your payments to choose as many or as few targets as you'd like.
