I'm afraid I haven't much else to say, just this crash report to provide.
crash-2020-11-18_22.02.55-client.txt

see if the new release fixes this

It seems to be fixed, but I haven't tested with the exact same mod lineup as before.

The crash fixed by the most recent update was not this one.

hmm are you sure that it isn't a different crash this time?

This is the new crash report generated by adding BetterSlabs to the same mod lineup as the previous. They appear to be identical, with the exception of one number in a few places.
crash-2020-11-19_18.02.03-client.txt

I have the same stacktrace, however I only started getting after upgrading to the latest Fabric loader. I don't remember which version I was on before for which it loaded fine:

java.lang.NullPointerException: Initializing game at java.io.Reader.<init>(Reader.java:78) at java.io.InputStreamReader.<init>(InputStreamReader.java:72) at dev.bodner.jack.betterslabs.client.BetterslabsClient.lambda$createPack$2(BetterslabsClient.java:55) at dev.bodner.jack.betterslabs.client.BetterslabsClient$$Lambda$6389/1047399172.accept(Unknown Source) at com.swordglowsblue.artifice.impl.ArtificeResourcePackImpl.<init>(ArtificeResourcePackImpl.java:80) at com.swordglowsblue.artifice.api.ArtificeResourcePack.ofAssets(ArtificeResourcePack.java:128) at com.swordglowsblue.artifice.api.Artifice.registerAssets(Artifice.java:50) at com.swordglowsblue.artifice.api.Artifice.registerAssets(Artifice.java:29) at dev.bodner.jack.betterslabs.client.BetterslabsClient.createPack(BetterslabsClient.java:36) at net.minecraft.class_310.handler$zph000$MinecraftClient(class_310.java:5866) at net.minecraft.class_310.<init>(class_310.java:592) at net.minecraft.client.main.Main.main(Main.java:177) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:224) at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:141) at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:27)