Combo 1
Requires: Muldrotha, the Gravetide must be on the battlefield. Kaya's Ghostform must be on the battlefield. Altar of Dementia must be on the battlefield. Lotus Petal must be on the battlefield. Kaya's Ghostform attached to Muldrotha.
Steps
1. Activate Altar of Dementia by sacrificing Muldrotha.
2. Kaya's Ghostform triggers, returning Muldrotha to the battlefield.
3. Resolve the Altar of Dementia's ability, causing target player to mill six cards.
4. Activate Lotus Petal by sacrificing it, adding b.
5. Cast Kaya's Ghostform from your graveyard by paying b, targeting Muldrotha.
6. Cast Lotus Petal from your graveyard by paying 0.
7. Repeat.

Results: Infinite death triggers. Infinite ETB. Infinite LTB. Infinite mill. Infinite sacrifice triggers. Infinite self-mill.

Combo 2
1. Activate Lotus Petal by tapping and sacrificing it, adding one mana of any color.
2. Cast Lotus PetalLotus Petal from your graveyard by paying ({0} magic symbol)  Magic Symbol (0).
3. Displacer Kitten triggers, blinking Muldrotha.
4. Repeat.

Results: Infinite colored mana.Infinite storm count.