Those are some ways to get Seal Scrolls, some methods are for higher levels but i doubt you`re level freezing at 50 so they can help.

1.Make every mission in Monthly Event or at least enough missions to get 300 points, you can get 2 seals scrolls per week.

2.Login everyday, you`ll get 1 seal from 5 logins and 1 seal from 17 logins.

3.Participate in Great Ninja War, you have a chance to get a pack which can contain 5, 8 or 10 seals. You dont have a 100pc chance to get a pack, the leader gives them and they`re only 10 at max.

4.Participate in Timed Events everyday, get Sun Scrolls and you can buy Seal Scroll Fragments from Groceries.

5.Do the ranked arena and try to reach the higher rank you can. You have a first reward which can give you 2 seals and you have the season rewards who can give you 6 seals at most but it requires to hit 6 paths which could be kinda hard but not impossible. You`ll get the season rewards at the end of the month.

6.Increase your power and you can get seals from power reward but its only one time.

7.By leveling up you can get seals aswell, lv 70 and lv 90 gives you 2 seals each.

8. Do the Survival Trial everyday, you have a chance to get a max of 2 seals per day if you re lucky.

9.Check your Ninja Handbook and do the missions from there, some missions gives you seals as reward.

10.Increase the bond level of ninjas at home. Some of them gives you Seal Fragments. You`ll get rewards from them at level 5, 10, 15 and 20. Level 20 is the maximum you can get.

11.Check the Hot Topics every week and get all free rewards you can. Sometimes you can get Seals aswell

12.Reach 100 acivity points in Daily Preactive and you`ll get 2 Seal Fragments.

13.Do the Weekend Missions every Saturday and Sunday. Chase Missions, Lucky Draw and The puzzle can give you Seals and Seal Fragment.

14.Check the Black Market everytime, it can give you 3 Seal Fragments for 80k coins.

If i`m wrong with something or i missed something i`ll ask for someone else to correct me or add. Thanks