Basic Yoga poses aren't necessarily easy, however they could be considered the basic building blocks or a reasonably complete yoga practice.
My own understanding of a "complete" yoga practice is in part inspired by a teacher training course I took with Andrey Lappa. In his universal freestyle yoga, a complete yoga practice included working on all the joints of the body in a balanced fashion. So if your yoga sequence includes forward bends for the spine then you should also include some basic yoga poses where the spine is bent backwards.
One way to begin a yoga practice, particularly in the ashtanga tradition is with sun salutations.
Sun salutations (or fun salutations) focus more on movement as opposed to holding a pose and can be a good way to warm up the hips, spine and arms, though mostly in the forward bending and backward bending directions.
I've grouped backbends for both the hip and spine under backbending yoga poses.
Forward bends for the hip and spine are shown under forward bending yoga poses.
For a focus on hamstring stretches (which are forward bends for the hips with the knees straight) you can check out hamstring stretches. This page focuses mainly on standing hamstring stretches since they are a little bit easier, especially if hamstring flexibility is limited.
Note that forward bends and backbends are counterposes for each other, however these terms are a little bit two general.
Remember that if you are backbending the spine then include a forward bend for the spine to counterbalance it.
If you are backbending the hips, then the counterpose is a forward bend for the hips.
For more on counterposes see the counterposes page.
Twisting yoga poses are another type of basic yoga pose and are often intermingled with binding pose and arm balances.
Twisting poses can be used to increase ribcage flexibility as well as shoulder and hip flexibility.
Twisting poses can be thought of as self-balancing, but it depends on the position of the leg and arms. I
f you have a twisting pose where a thigh is externally rotated then you need a pose where the thigh is internally rotated to balance it.
Also if you have a pose where the arm is internally rotated, then balance it with a pose where the arm is externally rotated.
Another type of basic yoga pose is binding yoga poses. These require some flexibility but are fun to get into (or challenging).
When binding, the bind itself changes the tension distribution in the body.
Binding is a little bit like using a prop, it can allow one part of the body to relax because it is supported.
In a binding yoga pose the bind is what allows a part of the body to relax.
Arm balances are like binds because one part of the body, generally a knee or some part of the leg, rests on another part of the body, usually the upper arm.
Because one part of the body rests on another it is easier to support the weight of the body while doing arm balances.