The first two "Pendulumgraph" cards, "Time Pendulumgraph" and "Star Pendulumgraph", prevent the opponent from targeting your Spellcaster monsters with Trap and Spell effects respectively. In addition, the first enables destruction of both opposing cards and your own "Magician" Pendulum monsters, while the second lets you search for other "Magicians" from your deck whenever those get destroyed.
The Pendulum Ritual Monster "Odd-Eyes Pendulumgraph Dragon" has no direct synergy with the Continuous Spells, but inflicts damage each time your opponent Special Summons from the Extra Deck, can negate the activation of a Spell/Trap card and destroy it, and can Special Summon an "Odd-Eyes" monster from the Extra Deck if it was Ritual Summoned when its effect places it in the Pendulum Zone.
"Purple Poison Magician", "Black Fang Magician" and "Double Iris Magician" work well with "Pendulumgraph" cards, as their effects activate whenever they are destroyed, with "Iris" searches for them. "Sky Iris" has good synergy with decks utilizing those cards.
As per the New Master Rule, the use of both Pendulumgraph Spells at a time, especially within a "Pendulum Magician" deck, will cause the player to have problems using Spell and Trap cards. Plan wisely before activating.