Keeper of the Lake looks to be delayed indefinitely but if you are looking for a similar vibe, Lover Merman seems to be it. Also billed as a BL with a Merman lead, this is supposed to have drama, romance, mystical lore and more.

Lover Merman is a Thailand production.
Keeper of the Lake was to be from the Philippines.

Both are LGBT dramas with male mermaids (aka mermen) involving “romance”.

Lover Merman is from Thailand whereas Mermaid’s Jade is from China.

Both Dramas about male mermaids aka Merman (mermen). 49 Days was a bromance but Lover Merman is an actual BL.

49 Days with a Merman is a Taiwanese production.
Lover Merman is a Thailand production.

In both After Sundown and Don’t Sleep, the main characters are dealing with a curse and malevolent ghosts. Both also involve sleep as an aid for the curse. Both are suspenseful and have intense scenes. Don’t Sleep is darker and grittier than After Sundown but both have very ominous vibes when watching. After Sundown has romance involved in its plot. Both movies are also Thai productions.

Both dramas have duality: set in both the real world and a virtual one. Both are to find a partner to be a “boyfriend”.

Monthly Boyfriend is a straight romance from South Korea.

Customized Companion is a gay thriller/romance movie from China.

The Director Who Buys Me Dinner and Old Fashioned Cupcake for me are like two sides of a coin. The are similar in that it’s a workplace setting, superior/subordinate relationship that is at first resisted or ignored by one side. Old Fashioned Cupcake is more light and fluffy where The Director Who Buys Me Dinner is heavier with more depth and a past with it.

Both of these are BL (gay romances).

Old Fashioned Cupcake is a Japanese production.
The Director Who Buys Me Dinner is a South Korean production.

Beside You and Caged Again are both BL Dramas that involve animal shifters. Both are also Thailand based productions.

Bake Me Please and Bite Me are both Thai BL Dramas with an overall similar vibe to them. They both focus on an established famous chef and an aspiring one. Bite Me focuses on main and side dishes whereas Bake Me Please is desserts.

Both are Thai BL Drama Series that have a gangster vibe to them. In The Heart Killers, it is about a pair of hitmen brothers and a police spy and his mechanic friend. In Jack & Joker, it is about an ex-convict / thief and an enforcer for the mafia.

Both The Heart Killers and Long Time No See are centered around a hitman based storyline that also includes BL or Gay Romance.

The Heart Killers is a Thai series.
Long Time No See is a South Korean film.

***POSSIBLE SPOILERS BELOW***

Zomvivor and Dead Friend Forever - DFF are horror dramas that are about upper secondary (high school) students and their attempts at survival. Neither are for the feint of heart.

While both are suspenseful shows, Zomvivor is with Zombies whereas Dead Friend Forever is an unknown entity that gradually is revealed.

Both are Thai productions with large main casts.

All of Us Are Dead and Zomvivor are both horror shows that are Zombie Outbreak in school settings where victims of a virus/illness are turned into zombies and include students and faculty alike.

All of Us Are Dead is a South Korean production.
Zomvivor is a Thai production.