These Keepsakes are great options when you don't need a God's Keepsake and want to save the S-tier Keepsakes for more difficult regions. They aren't as universally impactful as those in higher tiers, and each has potential weaknesses to equipping.
Luckier Tooth
Almost as good as the top two,
Luckier Tooth grants a one-time use Death Defiance that restores up to 151 health based on the rank. Since it can only be used once per run, it's not as strong as the top two Keepsakes. However,
Luckier Tooth's benefit is guaranteed and not limited by RNG offerings or a limited 10-second window to clear the encounter.
Remember that if you are running
Strength (XXIII), you'll only activate its damage reduction and boost AFTER you've used
Luckier Tooth.
White Antler
A favorite of speedrunners,
White Antler transforms
Melinoë into a glass cannon. If you plan on taking White Antler into the final region, look for
Success Rate or
Cherished Heirloom to increase the Crit chance.
Although your damage increases to truly insane levels, the trade-off of being limited to 30 health, no matter how much you previously had, is very punishing. Sometimes it works out because with high enough dps you can phase out bosses before they get a chance to unleash their attacks.
Unless you absolutely cracked, you should only every use
White Antler in standard runs, and not in regions where you have
Vow of Rivals activated.
Metallic Droplet
A common use for
Metallic Droplet is the Underworld's third region when the timer is a concern. The large locations in the Fields can burn away precious time, so the increased movement and attack speed help to make up that.
Unfortunately, many players will find it difficult to make it to the region's Guardian before the
Metallic Droplet's benefits expire, so it may not be helping you against the hardest foe.
In Magick builds, the increased channeling speed is very impactful. Consider trying out
Metallic Droplet next time you're spamming Omega Moves.
Experimental Hammer
Every Aspect has 1 or 2 Hammers that massively increase its power level. Some, like the
Zorephet's
Psychic Whirlwind, alter base properties of the Weapon, while others, like the
Descura's
Rapid Thrasher, simply increase Attack Speed stats.
The best time to equip
Experimental Hammer is the 3rd region. Once you've ranked it all the way up, the temporary Hammer Upgrade will last through the 3rd Region and into the final Boss, even after you've swapped to a new Keepsake.
If you haven't managed to grab the Hammer you were hoping for yet, the
Experimental Hammer is worth taking. Even if you don't get the one you want, on the next Hammer you find, you'll have one less upgrade in the RNG pool.
Be careful with Weapons like the Axe that have mechanic-altering Hammers like
Hell Splitter. Getting that from Experimental Hammer may completely disrupt your build and ruin your run!
Transcendent Embryo
The best part about
Transcendent Embryo is that even after unequipping it, you still get to keep your current
Chaos Boon! This makes
Transcendent Embryo an ideal 2nd or 3rd region Keepsake to equip.
Especially once you rank up the Keepsake to 3 stars, the Epic
Chaos Boons can be game-changing. The only reason we aren't placing it in S-tier is because of the randomness of
Chaos' boons. You may be hoping for increased Magick, and get stuck with increased resource farming.
Calling Card
Together with the other two Fates' Whim Keepsakes,
Calling Card is be very strong. You can either upgrade the rarity of a bunch of different Boons, or take two Boons from Common to Heroic!
Increasing Pom and rarity levels is worth getting rid of all Fates Arcana and God's Keepsakes. Even though you give up a lot of control over your build, the trade of off basically every Boon offered being upgraded means new rng builds are viable that would normally be bad builds.
Aromatic Phial
The 20% increased health recovery from fountains is just ok. The power to turn a common boon Heroic has huge potential in your runs. When you only have one common Boon, for example, a common
Heaven Flourish, turning it Heroic is well worth the use of a Keepsake because you almost double the Blitz damage.
The only reason we don't consider this to be a better Keepsake is that the selected common Boon is completely random, so you're taking a big gamble by sacrificing the use of another Keepsake by taking
Aromatic Phial instead.