These SARMs can be used individually or in combination to maximize muscle growth during bulking phases. However, it's important to note that proper diet, training, and dosage management are essential for achieving optimal results. 

1. LGD-4033 (Ligandrol): Known for its ability to promote significant gains in muscle mass and strength, Ligandrol is often used during bulking cycles. It's effective for increasing muscle size and improving overall body composition.
2. RAD-140 (Testolone): Testolone is another popular choice for bulking due to its potent anabolic effects. It's known to enhance muscle mass, strength, and endurance, making it ideal for users looking to pack on size and improve performance.
3. MK-677 (Ibutamoren): While not a traditional SARM, MK-677 is often grouped with SARMs due to its similar mechanism of action. It's known for increasing growth hormone levels, which can lead to improved muscle growth and recovery during bulking phases.
4. YK11: YK11 is a unique SARM that has been shown to promote muscle growth and enhance muscle strength. It works by increasing follistatin levels, which can lead to greater muscle development and improved performance during bulking cycles.