Death Saves Alternatives

Before we dive into any changes, let's review the basic rules first.

Death Saves in D&D 5e: What they are and how to use them.
Death saving throws are an important part of Dungeons & Dragons 5e. They decide if a character survives after being knocked out by damage.
The summary of the rules for them is:

• Rolling a d20: At the start of each turn after a character drops to 0 hit points, roll a d20. A roll of 10 or higher is a success, while a roll of 9 or lower is a failure.
• Stabilisation: If a character rolls three successes before three failures, they stabilise and are no longer in danger of dying. If they roll three failures, they die.
• Stabilisation Methods: Allies can stabilise a character by performing a DC 10 Wisdom (Medicine) check. If successful, the character becomes stable and stops making death saves.
• Healing: Any healing spell or potion that gives the character 1 hit point or more restores them to consciousness and resets the death saving throw count.

Understanding these rules is essential for managing character health and ensuring your party's survival.

Where are the potential problems:

Heals are saved till a character is at 0hp, as going to 0hp is less problematic than not going to 0hp
Characters getting knocked down to 0hp, healed, attack, knocked back to 0hp, healed, attack, etc

Stabilisation before healing

If the downed player is still making Death Saving Throws, you need to stabilise them before a heal actually restores hit points with a DC 10 Wisdom (Medicine) Check or a Heal from a spell or potion, which will now work as a guaranteed Wisdom (Medicine) Check.
This forces the process to be:

• Death Saves > Stabilisation > Ability to be Healed.

This makes bringing a player back up, and potentially a two-action, two-heal economy.

You Can Lose Levels

On each failed Death Save, you lose a level.
You can still fight till you go down, but it now has a greater risk of costing you levels as well.

Use New Exhaustion Rules To Allow Actions

Under these new rules, while a character is exhausted, they gain an exhaustion level as before; however, rather than having static effects for each level, the exhaustion affects saving throws, spell save DCs, ability checks, or attack rolls. When a player makes a d20 roll, they must subtract their exhaustion level from it, so a character with four levels of exhaustion would have to subtract four from their results.
When a character reaches zero hit points, they fall prone and gain the new dying condition. At the start of each turn, the DnD player rolls death saves as normal, but can also use either an action, bonus action, or movement. They can only choose one of these, and once they have used this action, their turn ends.
However, using these actions has consequences that increase exhaustion. Using an action makes the DnD player gain three levels, and a bonus action results in just one level. Although characters can move, they cannot stand up, so they must crawl or roll away from danger. Players can also use their reactions, but doing so results in gaining one level of exhaustion.

Downed Players Take Levels Of Exhaustion

Even using the current DnD exhaustion rules, DMs can change how death-saving throws work in their campaigns. Another suggestion would be that players could take a point of exhaustion for every round they are down. So instead of rolling a d20 to see if they die, they have up to six rounds (2014 rules) or ten rounds (2024 rules) to do limited actions.
When a character falls to zero hit points, they would automatically take a point of exhaustion to simulate bleeding out. Then every round, they can either perform one action or move, but not both. This would allow players to perform medicine checks on themselves or use magical healing, or continue to attack if they really wanted. Depending on the situation, a player might immediately heal themselves or try to take down the big bad who is on their last legs. Either way, the aim is to give the downed DnD player more choices.

Damage Causes Exhaustion

Rather than death saves, a player dropping to zero hit points would take a point of exhaustion every time they take more damage. This keeps the player engaged, takes death out of the realms of chance with d20 rolls, and gives them more chances to stay alive.
Players can choose to retreat and heal themselves or stay in the fight and go down swinging. This is a great alternative as it balances risk with rewards and requires players to be mindful of their resources.
When a DnD character goes to zero hit points, they will fall prone to simulate the toll the battle has taken on them. However, players can still move slowly without standing up, allowing them to retreat to get to another ally if needed. With this system, players can still make attacks, although at a disadvantage, and for spellcasters, no concentration spells can be cast as they fight to remain conscious.

Phoenix Rising

Death is just part of the story. As a hero, you are expected to die.
With this, there are no death saves; you can be downed only 7 times ever, the 8th down is permanent death.
But when you are reduced to 0 HP, at the end of the following turn, you rise fully restored (as if Long Rested).

Amped up Phoenix Rising

Just as with standard Phoenix Rising, Death is just part of the story; as a hero, you are expected to die. Again with this, there are no death saves; you can be downed only 7 times ever, the 8th down is permanent death.
But when you are reduced to 0 HP, at the end of the following turn, you rise fully restored (as if Long Rested).
And go up a level! Yes, dying makes you more powerful.

Mortal Wound

Once you mechanically die, your character is marked for death, and you’ll cross the threshold soon.
Generally, your character will stabilise and become conscious, but with a mortal wound that cannot be healed.
Typically, at the end of the combat encounter or session or whenever your GM determines it makes the best narrative sense, with no chance of resurrection.

Last Breath

When you’re dying, you take your Last Breath. You catch a glimpse of the afterlife or the celestial world that awaits (the GM will describe it). Then roll 2d6 (just roll, no modifiers).

• On a 10 or higher, you’ve cheated death — you’re in a bad spot, but you’re still alive and stabilised.
• On a 7–9, a celestial power will offer you a bargain. Take the pact and stabilise, or refuse and pass into the realm of Death. The bargain will usually be a quest that will come at great cost, often changing your character’s personality and goals.
• On 6 or lower, your fate is sealed. You’re marked for death, and you’ll cross the threshold soon. The GM will tell you when. Generally, your character will stabilise and become conscious, but with a mortal wound that cannot be healed. The GM may allow you to play your character until the end of that game session or whenever your GM determines makes the best narrative sense.

The Last Breath is that moment standing between life and death. Time stands still, and the dying character glimpses the afterlife. This could be anything from a Force Ghost, a guardian angel, or Death himself. Even those who do not pass beyond into eternity catch a glimpse of the other side and what might await them — friends and enemies past, rewards or punishment for acts in life or other, stranger vistas. All are changed in some way by this moment—even those who escape.
The key thing to remember is that a brush with death, succeed or fail, is a significant moment that should always lead to change.