Responsibility assignment matrices

RACI model

Responsible – works to perform the activity
Accountable – final approving authority, only one per task, must also ensure ensures the prerequisites of the task are met
Consulted – provide recommendations or opinions, typically subject-matter experts
Informed – are kept updated on the progress and status of the activity

Verifier: The role responsible for checking that the product meets certain criteria or standards.
Signatory: The role responsible for authorizing the work before it proceeds or is considered complete.

Another variation similar to RACI:

Contributes: Those who contribute to or provide input for the activity.
Leads: Those who lead and ensure the task is executed.
Approves: Those who approve or review the work.
Monitors: Those who monitor progress and ensure compliance and standards are met.

More geared towards clarify decision-making roles, seemingly in a consultancy workmode.

R = Recommend – gathers relevant input and proposes a course of action, possible alternatives, pros and cons
A = Agree – formal approval of a recommendation; A and R work together to come to a mutually satisfactory proposal for the Decider.
P = Perform – executes or implements the decision once it is made. Good practice is to involve them early in the process to gather input.
I = Input – provides relevant information to the Recommender and Decider. More narrow in scope than Recommenders, who should consider all input.
D = Decide – single person ultimately accountable for making the final decision, committing the group to action and ensuring the decision gets implemented.