Just realised that the CIMB Visa Infinite i also grants unlimited access to Priority Pass airport lounges worldwide, which brings the number of credit cards granting unlimited Priority Pass lounge access in Malaysia to 6:

1. Standard Chartered Priority Banking Visa Inifinite
2. Citi Prestige World Elite MasterCard
3. UOB Privilege Banking Visa Inifnite
4. Maybank World MasterCard
5. CIMB Visa Infinite i
6. Alliance Visa Infinite.

Visa Infinite cards are not all by invitation. It depends on the respective banks.

The requirements and annual fees:

1. Standard Chartered Priority Banking Visa Infinite
    - Be a Priority Banking customer with Asset Under Management (AUM) of RM250,000
    - Annual Fee RM800, waived with annual spending of RM10,000

2. Citi Prestige World Elite MasterCard
    - Annual income requirement of RM200,000
    - Annual Fee RM1,000
    - Even if you are a Citigold customer, you still need an annual income of RM200,000 to apply

3. UOB Privilege Banking Visa Infinite
    - Be a Privilege Banking customer with AUM of RM500,000. Not sure if higher AUM required to be invited for the VI card
    - Annual Fee RM1,800

4. Maybank World MasterCard
    - Annual income requirement of RM240,000
    - Annual Fee RM1,000, waived with annual spending of RM120,000

5. CIMB Visa Infinite i
    - Either annual income requirement of RM1 million or AUM of RM1 million
    - No Annual Fee

6. Alliance Visa Infinite
    - Either annual income requirement of RM150,000 or be a Privilege Banking customer with AUM of RM200,000
    - Annual Fee RM800, waived with annual spending of RM30,000 and waived for Privilege Banking customer

To answer your question, I'd say the Alliance Visa Infinite would be the easiest to be approved, both in terms of annual income requirement and by AUM with the bank.