Emissary of Despair

Tempo is a way to describe decks focusing on heavy interaction with efficient mana usage. Tempo decks play a few threats early, and try to chip away opponents HP and resources. Tempo decks are not the fastest decks causing damage, and aim to dragging the game a bit longer, and preventing opponents plans with right timed removals.

Saboteur is an effect on a creature triggered whenever the creature deals combat damage to an opponent. Many saboteur creatures have evasion and can wreck havoc with their effects if unanswered.

Unblockable creatures often have strong evasion, like flying or fear, or they are simply unblockable. Highly evasive creatures tend to have lower power to balance the strong effect of free damage in combat and tend to have lower toughness too.

The ways to discard are plenty: cycling, rummaging, end steps discard phase, to name a few. Discard decks are built around triggers from discarding, like madness and synergizes well with reanimating.

White has many great support spells and permanents for +1/+1 counters theme. Counters theme is often combined with White-weenie or token strategy and turns the small creatures into a formidable force.