Can I use the replay mod while doing a run? I know that obs is better but Is for taking custom screenshots (for thumbnail)

no there are only certain mods that are allowed and replay mod isn't one of them

just make the thumbnail on a different world after the run

Replay mod 

Khalooody

EllaTAS

Bruh_Banana

Fe_10

Minecraft: Java Edition

Palumn

KEN11432MCSR

zelariow

1.2.1

1.2.2

1.2.3

1.2.4

1.2.5

1.3.1

1.3.2

1.4.2

1.4.4

1.4.5

1.4.6

1.4.7

1.5.1

1.5.2

1.6.1

1.6.2

1.6.4

1.7.2

1.7.4

1.7.5

1.7.9

1.7.10

1.8.1 Easy

Normal

Hard

Hardcore

1.8.2

1.8.3

1.8.4

1.8.5

1.8.6

1.8.7

1.8.8 4 Players

5-9 Players

10+ Players

1.8.9

1.7.6

1.7.7

1.7.8

1.9.1

1.9.2

1.9.3

1.9.4

1.10

1.11.2

1.11

1.12

1.12.1

1.12.2 2 Players

3 Players

1.7.3 Set Seed

Random Seed

1.0-1.6

1.8-1.11

No F3

1.13

1.13.1

1.13.2

1.10.2

1.14

1.14.2

1.14.3

1.14.4

1.15

1.15.1

1.15.2 Pre 1.8

1.13-1.15

Pre 1.9

1.14+

1.9-1.15

Vanilla

Version

Difficulty

Players

Seed Type (Any% Glitchless)

Version Range (AA)

Seed Type (Any%)

Seed Type

Seed Type (Any% Glitchless Peaceful)

Seed Type (AA)

Version Range (AAdv)

Seed Type (AAdv)

Version Range (Any% Glitchless)

Version Range (Any%)

Version Range (Any% RSG Co-op)

Mods

Version Range (Any% Glitchless (Peaceful))

Version Range (Any% (Peaceful))

Version Range (Any% Glitchless (Demo))

Player Count (AAdv Co-op)

Seed/Glitch (AAdv Co-op)

Version Range (AAdv Co-op)

Seed Type (Combined Any%)

Seed Type (Any% Time Travel)

Seed type (Any% Glitchless Co-op)

Splits (Combined Any%)

If you save & quit/close the game at any point during the run, choose External.

Internal/External (Any%)

Changed version in Ninjabrain-bot resource:

-   [Ninjabrain-bot](https://github.com/Ninjabrain1/Ninjabrain-Bot/releases/tag/1.5.1) [Ninjabrain1] (up to v1.5.1)

Ensure measurements are still accurate after updating, especially with regards to tall resolutions/boat measurements - read the changelog 

Ninjabrain-Bot v1.5.1

Updated Legal Mods

Minecraft

Minecraft Speedrunning Questions Thread

Form for requesting custom map / server leaderboards

SpeedrunIGT

Gamma stuck

IS THIS THE BEST SEED FOR MINECRAFT SPEEDRUNING?

Awesomecuber

AprilSR

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nwolc

Luminosity

Droucked

ElRichi

DrGuy

Keima

Winrar

Specnr

AlEmeralds

audioSalix

gaylea

YUMmy_Bacon5

BSRF

luvvlyjude

taffel

Hayley

tildejustin

drip120

SirJeffersREBEL

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r0hkx

zBlackie_

Haim

Ame_

Leonn

leto_saa

escaperoftheend

Deadpool

Framesarecool

Michal_Alice

Secretivity11